Water jacket spacer structure

Abstract

To provide a water jacket spacer structure capable of being easily inserted into a water jacket during manufacturing, and capable of sufficiently cooling an upper part of a bore during driving of an engine.SOLUTION: A water jacket spacer 12 inserted into the water jacket comprises a spacer body member 120 formed using a resin material, a contact member 121, and an expandable member 122. The contact member 121 is formed using a metal material. The contact member 121 is configured to take a first position spaced apart from an outer wall surface 11a of a cylinder bore wall 11 when the water jacket is not filled with coolant, and to take a second position in contact against the outer wall 11a of the cylinder bore wall 11 when the water jacket is filled with the coolant.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to the structure of a water jacket spacer inserted into an engine's water jacket.

Background Art

[0002] In a water-cooled engine, a water jacket is formed on the outer side of the cylinder bore wall. A water jacket spacer may be inserted into the water jacket to adjust the temperature of the cylinder bore. For example, Patent Document 1 discloses a water jacket spacer composed of a combination of a spacer body, a heat insulating material, and an elastic body.

[0003] The water jacket spacer disclosed in Patent Document 1 has an elastic body that expands and contracts at a predetermined temperature. This water jacket spacer is configured such that the thickness dimension is smaller than the width dimension of the water jacket in a state where the elastic body is contracted. By inserting the water jacket spacer into the water jacket in a state where the elastic body is contracted in this way, high workability is said to be ensured.

[0004] On the other hand, when the engine is running, the temperature of the coolant in the water jacket may be equal to or higher than the predetermined temperature. In such a state, the elastic body of the water jacket spacer transitions to an extended state. As a result, the heat insulating material provided on the side opposite to the elastic body across the spacer body is pressed against the outer wall surface of the cylinder bore wall. In Patent Document 1, it is said that the temperature drop of the cylinder bore can be suppressed by bringing the heat insulating material into contact with the outer wall surface of the cylinder bore wall during engine operation.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, the temperature of the cylinder bore during engine operation is high on the top dead center side (upper part of the bore) and low on the bottom dead center side (lower part of the bore). A water jacket spacer that can correct such an imbalance in temperature between the upper part and the lower part of the bore has also been developed. Specifically, a water jacket spacer has been developed in which the distance from the outer wall surface of the cylinder bore wall is different vertically in the cylinder axis direction so that the flow path width is wide in the part surrounding the upper part of the bore in the water jacket and narrow in the part surrounding the lower part of the bore.

[0007] However, in the conventional water jacket spacer, the distance from the outer wall surface of the cylinder bore wall may undesirably change due to deformation or rattling caused by the flow of the coolant. In particular, when the flow path width changes due to deformation or rattling of the water jacket spacer in the upper part of the water jacket in the cylinder axis direction, sufficient cooling of the upper part of the bore cannot be performed.

[0008] The present invention has been made to solve the above problems, and an object thereof is to provide a water jacket spacer structure that is easy to insert into the water jacket during manufacturing and can sufficiently cool the upper part of the bore during engine operation.

Means for Solving the Problems

[0009] The structure of the water jacket spacer according to one aspect of the present invention is a water jacket spacer inserted into a water jacket formed between the outer wall surface of the cylinder bore wall of an engine and the inner wall surface of a cylinder block. When the top dead center side in the cylinder bore of the engine is upward and the bottom dead center side is downward, an upper wall portion closer to the inner wall surface at the upper part of the water jacket, and a lower wall portion that is connected to the upper wall portion and closer to the inner wall portion at the lower part of the water jacket. A spacer body member having a spacer body member, and one end of the spacer body member is fixed to the upper wall portion of the spacer body member, and can change its posture between a first posture spaced apart from the outer wall surface and a second posture in contact with the outer wall surface. And a long contact member having a higher thermal conductivity than the spacer body member and the cylinder bore wall. The contact member is configured to take the first posture when the water jacket is not filled with a coolant and the engine is not driven, and to take the second posture when the water jacket is filled with the coolant and the engine is driven.

[0010] In the water jacket spacer structure according to the above aspect, the water jacket spacer includes a contact member, and the contact member is configured to be able to take a first posture and a second posture. Specifically, the contact member is configured to take a first posture spaced apart from the outer wall surface of the cylinder bore wall in a state where no coolant is filled (for example, at the time of engine assembly). Therefore, when inserting the water jacket spacer into the water jacket of the cylinder block during engine assembly, it is possible to prevent the water jacket spacer from contacting the outer wall surface of the cylinder bore wall or the inner wall surface of the cylinder block. Therefore, by adopting the water jacket spacer structure according to the above aspect, high workability during engine assembly can be ensured, and deformation or breakage of the spacer body member of the water jacket spacer can be suppressed.

[0011] Further, the contact member is configured to assume a second posture in which the coolant is poured into the water jacket and the contact member contacts the outer wall surface of the cylinder bore wall while the engine is running. Therefore, when the engine is running after the pouring, the contact member contacts the outer wall surface of the cylinder bore wall, so that the spacer body member can be prevented from being deformed by vibration, liquid temperature (temperature of the coolant), or the like. Thus, cooling by the coolant in the water jacket around the upper part of the bore is ensured. Therefore, in the water jacket spacer structure according to the above aspect, it is possible to sufficiently cool the upper part of the bore that becomes hot when the engine is running.

[0012] Note that, in the above, "when the coolant is poured into the water jacket and the engine is running" means that at least at this time, the contact member should be in the second posture. Therefore, the contact member in the above aspect may change its posture to the second posture only after the pouring, or may change its posture to the second posture when the coolant rises above a predetermined temperature due to the driving of the engine.

[0013] Furthermore, in the water jacket spacer structure according to the above aspect, since the contact member has higher thermal conductivity than the spacer body member and the cylinder bore wall, when the engine is running, the heat of the upper part of the bore is also transferred to the coolant through the path via the cylinder bore wall and the contact member. Therefore, in the water jacket spacer structure according to the above aspect, the heat of the upper part of the bore when the engine is running can be transferred to the coolant with high efficiency.

[0014] Here, when the upper wall portion of the spacer body member is brought into contact with the outer wall surface of the cylinder bore wall in order to suppress the deformation of the spacer body member, since the spacer body member is made of a resin material, the thermal conductivity is low, and it becomes difficult to cool the cylinder bore wall with the coolant. Therefore, when the above configuration is adopted, the upper part of the bore becomes hot, leading to a decrease in engine performance (efficiency), and in the worst case, there is a concern that the engine may break due to knocking or the like.

[0015] On the other hand, in the water jacket spacer structure according to the above aspect, since it is provided with a contact member that contacts the outer wall surface of the cylinder bore wall when the engine is driven, deformation of the spacer main body member due to vibration or liquid temperature is suppressed, and heat transfer from the cylinder bore wall to the coolant is performed with excellent heat transfer performance. Therefore, in an engine that adopts the water jacket spacer structure according to the above aspect, it is possible to improve the thermal efficiency by advancing the knock angle, and it is possible to suppress the occurrence of a decrease in the above-described engine performance (efficiency) and knocking.

[0016] In the water jacket spacer structure according to the above aspect, it may further include a telescopic member that is fixed to the other end of the contact member and can change between a state in which the contact member contracts to take the first posture and a state in which the contact member expands to take the second posture.

[0017] In the water jacket spacer structure according to the above aspect, since it further includes a telescopic member that changes the posture of the contact member between the first posture and the second posture, after the engine is assembled, when the coolant is poured into the water jacket and the engine is in a driven state, the contact member is surely pressed against the outer wall surface of the cylinder bore wall, thereby suppressing deformation of the upper wall portion of the spacer main body member due to vibration during engine driving or the influence of the liquid temperature. Therefore, as described above, in an engine that adopts the water jacket spacer structure according to the above aspect, it is possible to improve the thermal efficiency by advancing the knock angle, and it is suitable for suppressing the occurrence of a decrease in engine performance (efficiency) and knocking.

[0018] In the water jacket spacer structure according to the above aspect, the telescopic member may be formed using cellulose sponge or bimetal.

[0019] In the water jacket spacer structure according to the above aspect, since cellulose sponge or bimetal can be adopted as a specific example of the constituent material of the expansion and contraction member, the contact member can be changed in posture between the first posture and the second posture. When the expansion and contraction member is formed using cellulose sponge, when the engine is assembled and the cellulose sponge is not immersed in the coolant, the expansion and contraction member is in a contracted state, so the contact member cannot be pressed against the cylinder bore wall. For this reason, a gap can be provided between the water jacket spacer and the wall surface surrounding the water jacket (the outer wall surface of the cylinder bore wall, the inner wall surface of the cylinder block), and high workability can be ensured during engine assembly or the like. Then, by injecting the coolant after the engine is assembled, the expansion and contraction member is in an extended state and acts on the contact member so that the contact member takes the second posture. From this, when the engine is driven, the upper part of the bore can be effectively cooled.

[0020] On the other hand, when the expansion and contraction member is constituted by bimetal, since the environmental temperature is about normal temperature during engine assembly, the expansion and contraction member is in a contracted state, and high workability can be ensured as in the case of adopting the above-mentioned cellulose sponge. Then, when the temperature of the coolant becomes a predetermined temperature or higher during engine operation, it acts on the contact member so that the contact member takes the second posture. From this, when the engine is driven, the upper part of the bore can be effectively cooled.

[0021] Note that the above-mentioned predetermined temperature refers to the lower limit temperature at which the engine becomes in a warm state. Specifically, it is a temperature of about 90°C.

[0022] In the water jacket spacer structure according to the above aspect, the spacer main body member may further have a connecting wall portion connecting the upper wall portion and the lower wall portion, the connecting wall portion has a through hole allowing the insertion of the contact member, and the expansion and contraction member is disposed below the connecting wall portion.

[0023] In the water jacket spacer structure according to the above aspect, since the expansion and contraction member is disposed below the connection wall portion, the expansion and contraction member does not inhibit the flow of the coolant above the connection wall portion when the engine is driven. Therefore, in the water jacket spacer structure according to the above aspect, the upper part of the bore during the driving of the engine can be cooled more effectively.

[0024] In the water jacket spacer structure according to the above aspect, the spacer body member may further have a connection wall portion connecting the upper wall portion and the lower wall portion, and the expansion and contraction member may be disposed on or above the connection wall portion.

[0025] In the water jacket spacer structure according to the above aspect, since the expansion and contraction member is disposed on or above the connection wall portion, it is not necessary to form a hole in the connection wall portion to allow the insertion of the contact member. For this reason, when the engine is driven, the flow of the coolant is separated above and below the connection wall portion, and the flow of the coolant in the region above the connection wall portion in the water jacket can be made difficult to be disturbed. Therefore, if the water jacket spacer structure according to the above aspect is adopted, the upper part of the bore during the driving of the engine can be effectively cooled.

[0026] Further, in the water jacket spacer structure according to the above aspect, the expansion and contraction member is disposed in the flow path of the coolant above the connection wall portion. For this reason, in the region above the connection wall portion in the water jacket, the flow path becomes narrower by the amount where the expansion and contraction member is disposed. In the region where the flow path becomes narrower in this way, the flow velocity of the coolant becomes faster. From this, it is suitable for releasing the heat of the upper part of the bore to the coolant. That is, the flow velocity of the coolant flowing in contact with the outer wall surface of the cylinder bore wall becomes faster, and even if the expansion and contraction member is disposed, the cooling efficiency through the outer wall surface of the cylinder bore wall is less likely to decrease, and the contact area with respect to the coolant increases by the amount of the contact member contacting the cylinder bore wall. Therefore, the upper part of the bore is cooled well by the increased amount.

[0027] In the water jacket spacer structure according to the above aspect, the spacer body member may be formed using a resin material, and the contact member may be formed using a metal material.

[0028] In the water jacket spacer structure according to the above aspect, the contact member is formed using a metal material and has higher thermal conductivity than the spacer body member formed using a resin material. Therefore, when the engine is driven, the heat generated at the upper part of the bore of the cylinder bore can be effectively dissipated to the coolant by pressing the contact member against the outer wall surface of the cylinder bore wall.

[0029] In the water jacket spacer structure according to the above aspect, the contact member may be configured to change its posture from the first posture to the second posture within the elastic range.

[0030] In the water jacket spacer structure according to the above aspect, since the contact member is configured to change its posture from the first posture to the second posture within the elastic range, it is possible to remove the water jacket spacer from the water jacket and then insert it back into the water jacket not only during engine assembly but also during engine maintenance. Therefore, by adopting the water jacket spacer structure according to the above aspect, it is possible to reuse it not only during engine assembly but also after maintenance, and it is also possible to reduce the cost during maintenance.

[0031] In the water jacket spacer structure according to the above aspect, the contact member may be formed using a shape memory alloy, and is configured to take the first posture when the temperature of the contact member is less than a predetermined temperature, and to take the second posture when the temperature of the contact member becomes equal to or higher than the predetermined temperature as the temperature of the coolant rises.

[0032] In the water jacket spacer structure according to the above aspect, since the contact member is configured using a shape memory alloy, the posture of the contact member changes depending on the temperature. That is, during engine assembly, etc., the environmental temperature is around normal temperature, so the contact member is also around normal temperature (a temperature lower than the predetermined temperature) and takes the first posture. Therefore, high workability can be ensured during engine assembly, etc. And when the engine is running, when the temperature of the coolant becomes equal to or higher than the predetermined temperature, the temperature of the contact member also becomes equal to or higher than the predetermined temperature and takes the second posture. From this, when the engine is running, the upper part of the bore can be effectively cooled.

[0033] In the water jacket spacer structure according to the above aspect, it is also possible that a plurality of the contact members are provided in a state of being dispersed in the circumferential direction with respect to one cylinder bore wall.

[0034] In the water jacket spacer structure according to the above aspect, a plurality of contact members are arranged in a dispersed manner in the circumferential direction with respect to one cylinder bore wall. For this reason, a plurality of contact locations of the contact members with respect to the outer wall surface of the cylinder bore wall can be dispersed and arranged in the circumferential direction, and the heat of the upper part of the bore can be released to the coolant while suppressing the variation in the circumferential direction. Therefore, if the water jacket spacer structure according to the above aspect is adopted, the upper part of the bore can be cooled while suppressing the variation in the circumferential direction.

[0035] In the water jacket spacer structure according to the above aspect, the engine may be an in-line multi-cylinder engine in which a plurality of cylinder bores are arranged in the cylinder row direction, and the contact member may be arranged so as to be able to contact a portion between the cylinder bores on the outer wall surface of the cylinder bore wall.

[0036] In the water jacket spacer structure according to the above aspect, since the contact member is arranged so as to be able to contact the portion between the cylinder bores on the outer wall surface of the cylinder bore wall, cooling of the upper part of the bore can be efficiently performed through the cylinder bore wall. This is because, when the engine is driven, the portion between the cylinder bores in the cylinder bore wall becomes hotter than other portions of the cylinder bore wall, and by pressing the contact member made of a metal material against the hot portion, heat can be dissipated to the coolant through the contact member.

Effect of the Invention

[0037] In the water jacket spacer structure according to each of the above aspects, insertion into the water jacket during manufacturing is simple, and the upper part of the bore can be sufficiently cooled when the engine is driven.

Brief Description of the Drawings

[0038]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0039] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the embodiments described below are illustrative of the present invention, and the present invention is not limited to the following embodiments except for its essential configuration.

[0040] In the drawings used in the following description, "X" indicates the cylinder row direction of the engine, "Y" indicates the intake / exhaust direction of the engine, and "Z" indicates the cylinder axis direction of the engine. Also, in the following description, the top dead center side in the cylinder axis direction of the engine is referred to as "upper", and the bottom dead center side is referred to as "lower".

[0041] [First Embodiment] 1. Configuration of Engine 1 The configuration of the engine 1 including the water jacket spacer 12 according to the first embodiment will be described with reference to Fig. 1. Note that in Fig. 1, only a part of the configuration of the engine 1 is extracted and shown.

[0042] As shown in Fig. 1, the engine 1 has four cylinder bores 1a to 1d arranged in the X direction. That is, the engine 1 is an in-line four-cylinder engine. Note that the type and number of cylinders of the engine are not limited to this.

[0043] The cylinder block 10 of the engine 1 is filled with cylinder liners 11 that surround the cylinder bores 1a to 1d. The cylinder liner 11 constitutes the cylinder bore wall, and the surface on the side opposite to the side facing each cylinder bore 1a to 1d is the outer wall surface of the cylinder bore wall.

[0044] The cylinder block 10 has a water jacket 1e provided in a state facing the outer wall surface of the cylinder liner 11. The water jacket 1e is a path through which the coolant introduced from the coolant inlet 1f circulates. In some cases, the cylinder block 10 is also provided with a coolant outlet 1g through which a part of the coolant that has flowed through the water jacket 1e is led out. Note that the remaining part of the coolant that has flowed through the water jacket 1e is led to a cylinder head (not shown).

[0045] A water jacket spacer 12 is inserted into the water jacket 1e. The insertion of the water jacket spacer 12 into the water jacket 1e is performed before the coolant is poured into the water jacket 1e. Note that the water jacket spacer 12 inserted into the water jacket 1e is in a state where the lower end side (the lower end side in the Z direction) of the water jacket spacer 12 abuts or is close to the bottom of the water jacket 12.

[0046] The water jacket spacer 12 includes a spacer body member 120 formed using a resin material (for example, PTFE, PPS, PA, etc.) and a contact member 121 fixed near the upper end of the inner surface of the spacer body member 120 and formed using a metal material (for example, steel plate, copper alloy, etc.).

[0047] 2. Arrangement of the contact member 121 in the water jacket spacer 12 The arrangement of the contact member 121 in the water jacket spacer 12 will be described with reference to FIG. 2.

[0048] As shown in Fig. 2, the spacer body member 120 has bore peripheral portions 120a to 120d formed so as to surround the periphery of each of the cylinder bores 1a to 1d in a plan view from the cylinder axis direction. The bore peripheral portions 120a to 120d are integrally formed so as to be continuous.

[0049] The contact members 121 are dispersedly arranged in two each on the respective bore peripheral portions 120a to 120d. The contact members 121 arranged on each of the bore peripheral portions 120a to 120d are arranged in a positional relationship facing each other in the Y direction (intake / exhaust direction).

[0050] 3. Contact Member 121 and Its Peripheral Configuration The contact member 121 and its peripheral configuration in the water jacket spacer 12 will be described with reference to Figs. 3 and 4. Fig. 3 shows a state where no coolant is poured into the water jacket 1e, and Fig. 4 shows a state where coolant is poured into the water jacket 1e.

[0051] As shown in Figs. 3 and 4, the spacer body member 120 has an upper wall portion 120e, a lower wall portion 120f, a connecting wall portion 120g, and a bottom wall portion 120h integrally formed. The upper wall portion 120e is formed so as to extend along the inner wall surface 10a facing the water jacket 1e in the cylinder block 10. The lower wall portion 120f is located below the upper wall portion 120e in the Z direction (cylinder axis direction), and is formed so as to extend along the outer wall surface 11a facing the water jacket 1e in the cylinder liner 11.

[0052] The connecting wall portion 120g is formed so as to extend in a direction orthogonal to the Z direction (cylinder axis direction) so as to regulate the lower end portion of the upper wall portion 120e and the upper end portion of the lower wall portion 120f. Note that a hole 120i penetrating in the plate thickness direction is provided in the connecting wall portion 120g. The bottom wall portion 120f is formed so as to extend in a direction orthogonal to the Z direction (cylinder axis direction) from the vicinity of the lower end portion of the lower wall portion 120f.

[0053] Here, the height position where the connection wall portion 120g in the Z direction is provided is a position set as the boundary between the bore upper portion A1 and the bore lower portion A2 in the cylinder bores 1a to 1d. This boundary position is a position experimentally grasped in advance for the portion that becomes equal to or higher than a predetermined temperature and the portion that is maintained below the predetermined temperature when the engine 1 is driven.

[0054] The contact member 121 is a long plate having a width of a predetermined dimension (for example, about 5 mm to 20 mm) in a direction orthogonal to the planes of FIGS. 3 and 4. The contact member 121 has an upper extension portion 121a, a bent portion 121b, a lower extension portion 121c, and an upper and lower extension portion 121d integrally formed. One end of the upper extension portion 121a is fixed near the upper end of the upper wall portion 120e of the spacer body member 120. The upper extension portion 121a is formed to extend inward in the Y direction (intake and exhaust direction) from the one end fixed to the spacer body member 120. And the upper extension portion 121a is formed to be inclined so as to go downward in the Z direction as it goes inward in the Y direction from the one end side.

[0055] One end of the bent portion 121b is connected to the other end (the inner end in the Y direction) of the upper extension portion 121a and is bent approximately 180° so as to draw an arc shape. One end of the lower extension portion 121c is connected to the other end (the lower end in the Z direction) of the bent portion 121b and is formed to extend outward in the Y direction (toward the outer wall surface 10a side of the cylinder block 10) from the one end connected to the bent portion 121b. And the lower extension portion 121c is formed to be inclined so as to go downward in the Z direction as it goes outward in the Y direction from the one end side.

[0056] When the upper extension portion 121a, the bent portion 121b, and the lower extension portion 121c are viewed as a whole from the side, they form a V shape.

[0057] The upper and lower extension part 121d has its upper end connected to the other end (the outer end in the Y direction) of the lower extension part 121c and is formed to extend downward. The upper and lower extension part 121d passes through a hole 120i formed in the connection wall part 120g of the spacer body member 120 at the middle part in its longitudinal direction. The upper and lower extension part 121d is formed to extend up to slightly above the bottom wall part 120h.

[0058] The water jacket spacer 12 according to the present embodiment further includes a telescopic member 122 in addition to the spacer body member 120 and the contact member 121. The telescopic member 122 is a member that expands when immersed in a coolant, and in this embodiment, it is formed using cellulose sponge as an example. The telescopic member 122 is fixed on the bottom wall part 120h of the spacer body member 120. And the lower end of the upper and lower extension part 121d is joined to the upper part of the telescopic member 122.

[0059] When the telescopic member 122 is not immersed in the coolant during the assembly of the engine 1 or the like, the telescopic member 122 is in a contracted state in the Z direction. Therefore, the upper and lower extension part 121d of the contact member 121 is pulled downward in the Z direction as a whole, and the other end (the connection part with the upper and lower extension part 121d) of the lower extension part 121c is also arranged at a position lowered downward in the Z direction. Thus, the V-shaped part composed of the upper extension part 121a, the bent part 121b, and the lower extension part 121c is in a state where the opening part on the outer side in the Y direction is open.

[0060] That is, when the expansion and contraction member 122 is not immersed in the coolant during the assembly of the engine 1 or the like, the distance between the outer wall surface of the upper wall portion 120e of the spacer main body member 120 (the surface facing the outer wall surface 10a of the cylinder block 10) and the position closest to the outer side surface 11a of the cylinder liner 11 in the bent portion 121b of the contact member 121 is narrower than the distance of the water jacket 1e. Therefore, when the water jacket spacer 12 is inserted into the water jacket 1e, there are gaps between the water jacket spacer 12 and both the inner wall surface 10a of the cylinder block 10 and the outer wall surface 11a of the cylinder liner 11 (arrows A3, A4). Note that the posture of the contact member 121 shown in FIG. 3 is the first posture.

[0061] On the other hand, as shown in FIG. 4, when the coolant is poured into the water jacket 1e after the assembly of the engine 1 is completed, the expansion and contraction member 122 is immersed in the coolant and expands as shown by the arrow B1. For this reason, the vertically extending portion 121d of the contact member 121 is pushed upward in the Z direction as shown by the arrow B2. Therefore, in the V-shaped portion of the contact member 121, the width dimension of the opening portion on the outer side in the Y direction becomes narrower.

[0062] When the contact portion 121 is deformed as described above, the contact member 121 is pressed against the outer wall surface 11a of the cylinder liner 11 by the bent portion 121b as shown by the arrow B3 (arrow B3). Depending on the material selection of the contact member 121, the pressing force against the outer wall surface 11a of the cylinder liner 11 may be strong. In this case, the reaction force of the pressing force against the outer wall surface 11a of the cylinder liner 11 shown by the arrow B3 acts, and the upper wall portion 120e of the spacer main body member 120 may approach or contact the inner wall surface 10a of the cylinder block 10. Note that the posture of the contact member 121 shown in FIG. 4 is the second posture.

[0063] However, from the perspective of cooling the upper part A1 of the bore, it is also preferable that the change in the posture of the contact member 121 from the first posture to the second posture prevents the upper wall portion 120e of the spacer main body member 120 from moving toward the inner wall surface 10a of the cylinder block 10. This is because, by preventing the upper wall portion 120e of the spacer main body member 120 from moving toward the inner wall surface 10a of the cylinder block 10, it is possible to suppress the widening of the flow path width between the outer wall surface 11a of the cylinder liner 11 in the water jacket 1e and the upper wall portion 120e of the spacer main body member 120, and thus suppress the decrease in the flow velocity of the coolant. As a result, it is possible to suppress the decrease in the flow velocity of the coolant at the upper part of the water jacket 1e, and the increase in the contact area of the contact member 121 with the outer wall surface 11a of the cylinder liner 11 is advantageous for cooling the upper part A1 of the bore.

[0064] Here, in the water jacket spacer 12 according to the present embodiment, the contact member 121 can transition between the state shown in FIG. 3 and the state shown in FIG. 4 within the elastic range. Therefore, for example, when trying to remove the water jacket spacer 12 from the water jacket 1e during maintenance, the coolant may be drained from the water jacket 1e so that the expansion and contraction member 122 is not immersed in the coolant and the state shown in FIG. 3 is achieved. By doing so, the removal work can be performed with high workability, and deformation and damage of the water jacket spacer 12 during removal can be suppressed.

[0065] 4. Effects In the water jacket spacer 12 according to this embodiment, the water jacket spacer 12 includes an abutting member 121, and the abutting member 121 is configured to be able to take a first posture (the posture shown in FIG. 3) and a second posture (the posture shown in FIG. 4). As described above, the abutting member 121 is configured to take a first posture in which it is separated from the outer wall surface 11a of the cylinder liner (cylinder bore wall) 11, such as when the engine 1 is assembled with the coolant not filled in the water jacket 1e. Therefore, when inserting the water jacket spacer 12 into the water jacket 1e during the assembly of the engine 1, it is possible to prevent the water jacket spacer 12 from abutting against the outer wall surface 11a of the cylinder liner 11 or the inner wall surface 10a of the cylinder block 10. Thus, by adopting the water jacket spacer 12 according to this embodiment, high workability during the assembly of the engine 1 can be ensured, and deformation and damage of the spacer body member 120 of the water jacket spacer 12 can be suppressed.

[0066] Further, as shown in FIG. 4, the abutting member 121 is configured to take a second posture in which it abuts against the outer wall surface 11a of the cylinder liner 11 in a state where the coolant is poured into the water jacket 1e. Therefore, after the injection of the coolant and during the driving of the engine 1, it is possible to suppress the upper wall 120e of the spacer body member 120 from being deformed or the like due to vibrations caused by the driving of the engine 1 or the influence of the temperature of the coolant. Thus, cooling of the coolant in the water jacket 1e around the upper part A1 of the bore is ensured. Therefore, by adopting the structure of the water jacket spacer 12 according to this embodiment, it is possible to sufficiently cool the upper part A1 of the bore, which becomes hot during the driving of the engine 1.

[0067] Furthermore, in the water jacket spacer 12 according to the present embodiment, the contact member 121 is configured to have a higher thermal conductivity than the spacer main body member 120 and the cylinder liner 11. Specifically, in the present embodiment, the spacer main body member 120 is formed using a resin material (e.g., PTFE, PPS, PA, etc.), while the contact member 121 is formed using a metal material (as an example, a steel plate, a copper alloy). Therefore, when the engine 1 is driven, the contact member 121 comes into contact with (is pressed against) the outer wall surface 11a of the cylinder liner 11, and thus the heat of the upper bore portion A1 is transferred to the coolant in the water jacket 1e through the cylinder liner 11 and the contact member 121. For this reason, if the water jacket spacer 12 according to the present embodiment is adopted, the heat of the upper bore portion A1 during the driving of the engine 1 can be efficiently transferred to the coolant.

[0068] Here, when the upper wall portion 120e of the spacer main body member 120 is brought into contact with the outer wall surface 11a of the cylinder bore wall 11 in an attempt to suppress deformation of the spacer main body member 120, since the spacer main body member 120 is made of a resin material, its thermal conductivity is low, and it becomes difficult to cool the cylinder bore wall 11 with the coolant. Therefore, when such a configuration is adopted, the upper bore portion A1 becomes high temperature, leading to a decrease in engine performance (efficiency), and in the worst case, there is a concern that the engine may break due to knocking or the like.

[0069] On the other hand, in the structure of the water jacket spacer 12 according to the present embodiment, since it is provided with the contact member 121 that comes into contact with the outer wall surface 11a of the cylinder bore wall 11 when the engine 1 is driven, deformation of the spacer main body member 120 caused by vibration or liquid temperature is suppressed, and heat transfer from the cylinder bore wall 11 to the coolant is performed with excellent heat transfer performance. Therefore, in the engine 1 adopting the structure of the water jacket spacer 12 according to the present embodiment, it is possible to improve the thermal efficiency by advancing the knock angle, and it is possible to suppress the occurrence of a decrease in engine performance (efficiency) and knocking as described above.

[0070] The water jacket spacer 12 according to this embodiment further includes a telescopic member 122 that changes the posture of the contact member 121 between a first posture and a second posture. Therefore, after the engine 1 is assembled, when the coolant is poured into the water jacket 1e and the engine 1 is in a driven state, the contact member 121 is surely pressed against the outer wall surface 11a of the cylinder liner 11, thereby suppressing the deformation of the upper wall portion 120e of the spacer main body member 120 due to vibrations during engine driving, the temperature of the coolant, and the like. Therefore, the engine 1 adopting the structure of the water jacket spacer 12 according to this embodiment is suitable for suppressing the occurrence of a decrease in engine performance (efficiency) and knocking as described above.

[0071] In the water jacket spacer 12 according to this embodiment, cellulose sponge is adopted as the constituent material of the telescopic member 122. Therefore, the posture of the contact member 121 can be changed between the first posture and the second posture without using complicated and expensive members.

[0072] In the water jacket spacer 12 according to this embodiment, since the telescopic member 122 is disposed below the connection wall portion 120g of the spacer main body member 120, the telescopic member 122 does not obstruct the flow of the coolant above the connection wall portion 122 when the engine 1 is driven. Therefore, if the water jacket spacer 12 according to this embodiment is adopted, the upper part A1 of the bore can be effectively cooled when the engine 1 is driven.

[0073] In the water jacket spacer 12 according to the present embodiment, as shown in FIG. 2, two abutting members 121 are circumferentially distributed (arranged to face each other in a plan view) with respect to one cylinder bore 1a to 1d. Therefore, it is possible to suppress the upper wall portion 120e of the spacer body member 120 from deforming in a part of the circumferential direction due to the vibration of the engine 1 or the influence of the temperature of the coolant, and it is possible to effectively perform heat transfer from the outer wall surface 11a of the cylinder liner 11 and the abutting member 121 to the coolant. Therefore, if the water jacket spacer 12 according to the present embodiment is adopted, the upper part A1 of the bore can be effectively cooled.

[0074] In the water jacket spacer 12 according to the present embodiment, since the abutting member 121 is configured to change its posture from the first posture to the second posture within the elastic range, not only at the time of assembling the engine 1 but also at the time of maintenance of the engine 1, etc., it is possible to take out the water jacket spacer 12 from the water jacket 1e and then insert it again into the water jacket 1e. Therefore, if the water jacket spacer 12 according to the present embodiment is adopted, it is possible to use it again not only at the time of assembling the engine 1 but also after maintenance, and it is also possible to reduce the cost at the time of maintenance.

[0075] As described above, by adopting the structure of the water jacket spacer 12 according to the present embodiment, the insertion into the water jacket 1e during manufacturing is simple, and the upper part A1 of the bore can be sufficiently cooled during the driving of the engine 1.

[0076] [Second Embodiment] The structure of the water jacket spacer 22 according to the second embodiment will be described with reference to FIG. 5. FIG. 5 is a cross-sectional view showing a partial configuration of the engine 2 in which the water jacket spacer 22 is adopted. In FIG. 5, members having the same configuration as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted below.

[0077] In the water jacket spacer 22 according to the present embodiment, the fixing position of the telescopic member 222 with respect to the spacer main body member 220 is different from that in the first embodiment.

[0078] As shown in FIG. 5, also in the water jacket spacer 12 according to the present embodiment, the spacer main body member 220 is made of a resin material, and the upper wall portion 220e, the lower wall portion 220f, the connecting wall portion 220g, and the bottom wall portion 220h are integrally formed. However, in the spacer main body member 220 of the present embodiment, no hole is formed in the connecting wall portion 220g, and the restricting wall portion 220k connected to the upper wall portion 220e and the restricting wall portion 220j connected to the upper surface of the connecting wall portion 220g are also integrally formed.

[0079] In the water jacket spacer 22, the telescopic member 222 is disposed at a portion between the upper wall portion 220e and the restricting wall portion 220j. The telescopic member 222 is made of cellulose sponge as an example, similar to the first embodiment, and expands as shown by the arrow C1 when immersed in the coolant. The upward position of the expansion of the telescopic member 222 is restricted by the restricting wall portion 222k.

[0080] The contact member 221 of the present embodiment is also made of a metal material (for example, a steel plate, a copper alloy) in the same manner as in the first embodiment. The contact member 221 of the present embodiment has an upper extending portion 221a, a bending portion 221b, and a lower extending portion 221c integrally formed, and is different from the contact member 121 of the first embodiment in that it does not have upper and lower extending portions. That is, in the present embodiment, the lower end of the lower extending portion 221c of the contact member 221 is directly joined to the telescopic member 222.

[0081] Also in the water jacket spacer 22 according to this embodiment, the elastic member 222 made of cellulose sponge expands (extends) as shown by the arrow C1 when immersed in the coolant. For this reason, the other end of the lower extension portion 221c of the contact member 221 fixed to the upper surface of the elastic member 222 (the end opposite to the end connected to the bent portion 221b) is lifted upward in the Z direction. By this action, the contact member 221 changes its posture from the first posture shown by the broken line to the second posture shown by the solid line. When the contact member 221 changes its posture to the second posture, similar to the first embodiment, the bent portion 221b of the contact member 221 is pressed against the outer wall surface 11a of the cylinder liner 11 as shown by the arrow C2.

[0082] The water jacket spacer 22 according to this embodiment is different from the first embodiment in the above points, but can achieve the same effects as the first embodiment.

[0083] Further, in the water jacket spacer 22 according to this embodiment, since the elastic member 222 is disposed on the connection wall portion 220g of the spacer main body member 220, it is not necessary to open a hole 121i (see FIGS. 3 and 4) that allows the vertical insertion portion 121d of the contact member 121 to pass through the connection wall portion 120g as in the first embodiment. For this reason, when the engine 2 is driven, the flow of the coolant is separated above and below the connection wall portion 220g, the mixing of the coolant above and below the connection wall portion 220g is suppressed, and the flow of the coolant in the region above the connection wall portion 220g in the water jacket 1e is hardly inhibited. Therefore, if the water jacket spacer 22 according to this embodiment is adopted, the upper bore portion A1 (see FIG. 3) can be effectively cooled when the engine 2 is driven.

[0084] In addition, in the structure of the water jacket spacer 22 according to the present embodiment, the expansion and contraction member 222 is disposed in a region above the connection wall portion 220g in the water jacket 1e. Therefore, in the region above the connection wall portion 220g in the water jacket 1e, the flow path becomes narrower by the amount where the expansion and contraction member 222 is disposed. In the region where the flow path becomes narrower in this way, the flow velocity of the coolant increases. From this, it is suitable for releasing the heat of the upper part A1 of the bore (see FIG. 3) to the coolant. That is, the contact area with respect to the coolant increases by the amount of the contact member 221 that contacts the outer wall surface 11a of the cylinder liner 11, and the upper part A1 of the bore is cooled well by this increased amount.

[0085] In the present embodiment, a restricting wall portion 220j is provided on the connection wall portion 220g to restrict the position of the expansion and contraction member 222, and a restricting wall portion 220k is provided on the upper wall portion 220e to restrict the upper limit position of the expansion and contraction member 222 during expansion. However, these restricting wall portions 220j and 220k are not essential components.

[0086] [Third Embodiment] The structure of the water jacket spacer 32 according to the third embodiment will be described with reference to FIG. 6. FIG. 6 is a cross-sectional view showing a partial configuration of the engine 3 in which the water jacket spacer 32 is employed. In FIG. 6, members having the same configuration as those in the first embodiment and the second embodiment are denoted by the same reference numerals, and the description thereof will be omitted below.

[0087] The expansion and contraction direction of the expansion and contraction member 322 of the water jacket spacer 32 according to the present embodiment is different from that of the second embodiment.

[0088] As shown in FIG. 6, also in the water jacket spacer 32 according to the present embodiment, the spacer main body member 320 is made of a resin material, and the upper wall portion 320e, the lower wall portion 320f, the connection wall portion 320g, and the bottom wall portion 320h are integrally formed. Further, the spacer main body member 320 of the present embodiment is also integrally formed with a restricting wall portion 320k connected to the upper wall portion 320e.

[0089] In the water jacket spacer 32, the expansion and contraction member 322 is disposed in a portion between the connection wall portion 320g and the regulation wall portion 320k, and is arranged such that the direction with a high elongation rate is the Y direction. The expansion and contraction member 322 is made of cellulose sponge as an example, similar to the first embodiment and the second embodiment, and expands (extends) toward the cylinder liner 11 as indicated by the arrow D1 when immersed in the cooling liquid.

[0090] The contact member 321 is made of a metal material (for example, a steel plate or a copper alloy) as in the first embodiment and the second embodiment. The contact member 321 of the present embodiment has an upper extension portion 321a, a bending portion 321b, an upper and lower extension portion 321c, and a bending portion 321d integrally formed. The upper and lower extension portion 321d is configured to extend in a substantially straight line so as to connect between the bending portion 321b and the bending portion 321d. The other end of the bending portion 321d (the end opposite to the end connected to the upper and lower extension portion 321c) is fixed to the inner surface in the Y direction of the expansion and contraction member 322.

[0091] Also in the water jacket spacer 32 according to the present embodiment, the expansion and contraction member 322 made of cellulose sponge expands (extends) as indicated by the arrow D1 when immersed in the cooling liquid. For this reason, the bending portion 321d of the contact member 321 fixed to the inner surface in the Y direction of the expansion and contraction member 322 is moved inward in the Y direction (radial direction). By this action, the contact member 321 changes its posture from the first posture indicated by the broken line to the second posture indicated by the solid line. When the contact member 321 changes its posture to the second posture, the upper and lower extension portion 321c between the bending portion 321b and the bending portion 321d is pressed against the outer wall surface 11a of the cylinder liner 11 as indicated by the arrow D2.

[0092] The water jacket spacer 32 according to the present embodiment is different from the second embodiment in the above points, but can achieve the same effects as the second embodiment.

[0093] Further, in the water jacket spacer 32 according to the present embodiment, when the contact member 321 takes the second posture, the vertically extending portion 321c is configured to be in surface contact rather than point contact with the outer wall surface 11a of the cylinder liner 11. Therefore, the heat generated in the upper part A1 of the bores of the cylinder bores 1a to 1d can be effectively transferred to the coolant through the cylinder liner 11 and the contact member 321. Thus, if the water jacket spacer 32 according to the present embodiment is adopted, the contact member 321 is in surface contact with a wider range of the outer wall surface 11a of the cylinder liner 11 in the second posture than the contact members 121 and 221 of the first and second embodiments. Therefore, the upper part A1 (see FIG. 3) of the bore can be cooled more effectively when the engine 3 is driven.

[0094] [Modification Example 1] The structure of the water jacket spacer 42 according to Modification Example 1 will be described with reference to FIG. 7. FIG. 7 is a cross-sectional view showing a partial configuration of an engine 4 in which the water jacket spacer 42 is employed. In FIG. 7, members having the same configuration as those in the first to third embodiments are denoted by the same reference numerals, and the description thereof will be omitted below.

[0095] The shape of the contact portion of the water jacket spacer 42 according to the present embodiment with the cylinder liner 11 when the contact member 421 takes the second posture is different from that in the first to third embodiments.

[0096] As shown in FIG. 7, in the contact member 421 of this modification example, the portion connecting between the upper extending portion 421a and the lower extending portion 321c is formed by a multi-bending portion 421b. The multi-bending portion 421b has a plurality of bending portions. When the contact member 421 takes the second posture, as shown by the arrow E, a plurality of portions of the multi-bending portion 421b of the contact member 421 come into contact with the outer wall surface 11a of the cylinder liner 11.

[0097] The form of the contact member 421 of this modification example can be applied to the first and second embodiments. Even in this case, the same effects as those in the first and second embodiments can be obtained.

[0098] In addition, when the contact member 421 of this modification is adopted, when the contact member 421 takes the second posture, the multi-bending portion 421b contacts the outer wall surface 11a of the cylinder liner 11 not at one surface but at a plurality of surfaces. Therefore, the heat generated at the upper bore portion A1 of the cylinder bores 1a to 1d can be effectively transferred to the coolant through the cylinder liner 11 and the contact member 421. Thus, if the water jacket spacer 42 according to the present embodiment is adopted, the upper bore portion A1 (see FIG. 3) during the driving of the engine 4 can be cooled more effectively.

[0099] In the cross-sectional view of FIG. 7, when the contact member 421 takes the second posture, the contact between the contact member 421 and the outer wall surface 11a of the cylinder liner 11 is illustrated as point contact. However, actually, the contact member 421 is configured to be surface contact in the same manner as in the first to third embodiments.

[0100] [Fourth Embodiment] The structure of the water jacket spacer 52 according to the fourth embodiment will be described with reference to FIG. 8. FIG. 8 is a cross-sectional view showing a partial configuration of an engine 5 in which the water jacket spacer 52 is adopted. In FIG. 8, members having the same configuration as those in the first to third embodiments are denoted by the same reference numerals, and the description thereof will be omitted below.

[0101] The water jacket spacer 52 according to the present embodiment is different from the first to third embodiments in that the water jacket spacer 52 is composed of a spacer main body member 520 and a contact member 521 and does not include a telescopic member.

[0102] As shown in FIG. 8, also in the water jacket spacer 52 according to the present embodiment, the spacer main body member 520 is made of a resin material, and the upper wall portion 520e, the lower wall portion 520f, the connecting wall portion 520g, and the bottom wall portion 520h are integrally formed.

[0103] The contact member 521 is made of a metal material, similar to the respective contact members 121, 221, 321, 421 in the first to third embodiments and the first modification. However, in the first to third embodiments and the first modification, the respective contact members 121, 221, 321, 421 were formed using, for example, a steel plate or a copper alloy, whereas the contact member 521 in this embodiment is formed using a shape memory alloy.

[0104] The contact member 521 has an upper extension portion 521a, a bent portion 521b, a lower extension portion 521c, and an upper and lower extension portion 521d, similar to the contact member 121 in the first embodiment. Further, the contact member 521 also has a bent portion 521e that connects the lower extension portion 521c and the upper and lower extension portion 521d. In the contact member 521, the upper extension portion 521a, the bent portion 521b, the lower extension portion 521c, the bent portion 521e, and the upper and lower extension portion 521d are integrally formed.

[0105] In the contact member 521, the upper and lower extension portion 521d has its lower end (the end opposite to the end connected to the bent portion 521e) fixed to the upper surface of the connection wall portion 520g of the spacer main body member 520.

[0106] In the engine 5 provided with the water jacket spacer 52 according to this embodiment, after the coolant is poured into the water jacket 1e and the engine 5 is driven and the temperature of the coolant poured into the water jacket 1e is less than a predetermined temperature (for example, less than 90°C), as shown by the broken line, the bent portion 521e of the contact member 521 is in a state of being bent with a large curvature (with a small radius of curvature).

[0107] On the other hand, when the engine 5 is driven and the temperature of the coolant becomes equal to or higher than a predetermined temperature (for example, 90°C or higher), as shown by the solid line, the curvature of the bent portion 521e of the contact member 521 becomes smaller (the radius of curvature becomes larger) (arrow F1). As a result, the contact member 521 changes its posture from the first posture shown by the broken line to the second posture shown by the solid line, and the bent portion 521b is pressed against the outer wall surface 11a of the cylinder liner 11 as shown by the arrow F2.

[0108] The water jacket spacer 52 according to the present embodiment is different from the first to third embodiments in that it does not include a telescopic member, but the same effects as the first to third embodiments can be obtained.

[0109] Further, in the water jacket spacer 52 according to the present embodiment, by configuring the contact member 521 using a shape memory alloy, the posture of the contact member 521 changes by itself according to the temperature of the coolant. That is, in the water jacket spacer 52 according to the present embodiment, it is not necessary to include a telescopic member for changing the posture of the contact member 521, so with a small number of components, it is possible to effectively cool the upper part A1 of the bore (see FIG. 3) during engine operation.

[0110] Regarding the shape of the contact member 521, the shapes such as those in the third embodiment and the first modification can also be adopted.

[0111] Also, in the cross-sectional view of FIG. 8, when the contact member 521 takes the second posture, the contact between the contact member 521 and the outer wall surface 11a of the cylinder liner 11 is shown as point contact, but actually, the contact member 521 is configured to be in surface contact in the same manner as in the first to third embodiments and the first modification.

[0112] [Fifth Embodiment] The structure of the water jacket spacer 62 according to the fifth embodiment will be described with reference to FIG. 9. FIG. 9 is a cross-sectional view showing a partial configuration of the engine 6 in which the water jacket spacer 62 is employed. In FIG. 9, members having the same configuration as those in the first to third embodiments are denoted by the same reference numerals, and the description thereof will be omitted below.

[0113] The water jacket spacer 62 according to the present embodiment is different from the second embodiment in that a member made of bimetal is adopted as the telescopic member 622.

[0114] As shown in FIG. 9, in the water jacket spacer 62 according to the present embodiment as well, the spacer main body member 620 is made of a resin material, and the upper wall portion 620e, the lower wall portion 620f, the connecting wall portion 620g, and the bottom wall portion 620h are integrally formed. Further, the spacer main body 620 also has an anchor wall portion 620j that protrudes upward from the upper surface of the connecting wall portion 620g.

[0115] The contact member 621 is configured using a metal material (for example, a steel plate, a copper alloy) in the same manner as the respective contact members 121, 221, 321, 421 of the first to third embodiments and the first modification.

[0116] The contact member 621 has an upper extension portion 621a, a bent portion 621b, and a lower extension portion 621c in the same manner as the contact member 221 of the second embodiment. Also in the contact member 621, the upper extension portion 621a, the bent portion 621b, and the lower extension portion 621c are integrally formed.

[0117] The expansion and contraction member 622 of the present embodiment is composed of a plate-shaped or linear bimetal. One end of the expansion and contraction member 622 is joined to one end of the lower extension portion 621c of the contact member 621, and the other end is fixed to the anchor wall portion 620j of the space main body member 620.

[0118] In the engine 6 provided with the water jacket spacer 62 according to the present embodiment, when the coolant injected into the water jacket 1e has a temperature lower than a predetermined temperature (for example, lower than 90°C) while the engine 6 is being driven, the expansion and contraction member 622 is in a state of being bent with a large curvature (with a small radius of curvature) as indicated by the dashed line.

[0119] On the other hand, when the engine 6 is driven and the temperature of the coolant reaches a predetermined temperature or higher (for example, 90°C or higher), as shown by the solid line, the curvature of the expansion and contraction member 622 decreases (the radius of curvature increases) (arrow G1). As a result, the contact member 621 changes its posture from the first posture shown by the dashed line to the second posture shown by the solid line, and the bent portion 621b is pressed against the outer wall surface 11a of the cylinder liner 11 as shown by the arrow G2.

[0120] The water jacket spacer 62 according to the present embodiment is different from the second embodiment in that it includes an expansion and contraction member 622 made of bimetal, but the same effects as those of the second embodiment can be obtained.

[0121] Further, in the water jacket spacer 62 according to the present embodiment, by forming the expansion and contraction member 622 using bimetal, the resistance to the coolant flowing in the region above the connection wall portion 620g can be kept lower than in the case where the expansion and contraction member is formed using cellulose sponge. That is, in the present embodiment in which the expansion and contraction member 622 is formed using bimetal, it is possible to reduce the resistance to the flow by suppressing the projected area with respect to the flow of the coolant in the water jacket 1e to a small value. Therefore, if the water jacket spacer 62 according to the present embodiment is adopted, it is possible to more effectively cool the upper part A1 of the bore (see FIG. 3) when the engine 6 is driven.

[0122] In the present embodiment, the expansion and contraction member 622 is arranged above the connection wall portion 620g. However, similar to the first embodiment, it is also possible to arrange it below the connection wall portion 620g.

[0123] Also, in the cross-sectional view of FIG. 9, when the contact member 621 takes the second posture, the contact between the contact member 621 and the outer wall surface 11a of the cylinder liner 11 is shown as a point contact. However, actually, the contact member 621 is configured to have surface contact in the same manner as in the first to fourth embodiments and the first modification.

[0124] Further, regarding the form of the contact member 621, it is also possible to adopt the same form as the contact member 321 of the third embodiment or the contact member 421 of the first modification example.

[0125] [Modification Example 2] The structure of the water jacket spacer 72 according to the second modification example will be described with reference to FIG. 10(a). FIG. 10(a) is a cross-sectional view showing a partial configuration of the engine 7 in which the water jacket spacer 72 is employed. In FIG. 10(a), members having the same configuration as those in the first to fifth embodiments are denoted by the same reference numerals, and the description thereof will be omitted below.

[0126] The water jacket spacer 72 according to this modification example is different from the first to fifth embodiments and the first modification example in that four contact members 721 are arranged for each cylinder bore.

[0127] Specifically, as shown in FIG. 10(a), in the water jacket spacer 72 according to this modification example, four contact members 721 are fixed to the spacer body member 720 having the same configuration as those in the first to fifth embodiments and the first modification example for each cylinder bore. Each contact member 721 has the same configuration as any one of the first to fifth embodiments and the first modification example.

[0128] The four contact members 721 arranged for each cylinder bore are distributed in the circumferential direction. Each contact member 721 may be directed toward the center (cylinder axis) of the cylinder bore or may be slightly deviated from the center in the direction in which the posture changes with respect to the cylinder liner 11 when changing from the first posture to the second posture. The contact member 721 in this modification example is made of a metal material (for example, a steel plate, a copper alloy, a shape memory alloy, etc.).

[0129] The water jacket spacer 72 according to this modification is different from the first to fifth embodiments and the first modification in that four contact members 721 are arranged for each cylinder bore, but other configurations are the same. Therefore, even when the water jacket spacer 72 according to this modification is adopted, the same effects as those of the first to fifth embodiments and the first modification can be obtained.

[0130] Further, in the water jacket spacer 72 according to this modification, since there are four contact members 721 for each cylinder bore, at least when the engine 7 is driven, the heat generated at the upper part A1 of the bore (see FIG. 3) can be favorably transferred to the coolant not only through the outer wall portion of the cylinder liner 11 but also through the contact members 721. Thus, it is possible to more effectively cool the upper part A1 of the bore (see FIG. 3) when the engine 7 is driven.

[0131] In this modification, four contact members 721 are arranged for each cylinder bore. However, it is also possible to arrange three contact members 721 or five or more contact members 721.

[0132] [Modification 3] The structure of the water jacket spacer 82 according to Modification 3 will be described with reference to FIG. 10(b). FIG. 10(b) is a cross-sectional view showing a partial configuration of an engine 8 in which the water jacket spacer 82 is adopted. In FIG. 10(b), members having the same configurations as those of the first to fifth embodiments are denoted by the same reference numerals, and the description thereof will be omitted below.

[0133] The water jacket spacer 82 according to this modification is different from the first to fifth embodiments and the first and second modifications in that a contact member 821 is arranged so as to be able to contact the portion 11d between the cylinder bores in the cylinder liner 11.

[0134] Specifically, as shown in Fig. 10(b), the cylinder liner 11 has bore peripheral portions 11b and 11c surrounding the cylinder bore, and an inter-bore portion 11d which is the portion between the adjacent bore peripheral portions 11b and 11c in the X direction (cylinder bank direction). The inter-bore portion 11d is recessed inward in the Y direction (intake / exhaust direction) compared to the bore peripheral portions 11b and 11c.

[0135] When the engine 8 is driven, the cylinder liner 11 becomes hotter at the portion of the inter-bore portion 11d than at the bore peripheral portions 11b and 11c.

[0136] In the water jacket spacer 82 according to this modification, a contact member 821 is fixed to the inter-bore portion 820l of the spacer body member 820. The inter-bore portion 820l of the spacer body member 820 is a portion facing the inter-bore portion 11d of the cylinder liner 11 in the Y direction, and is located between a bore peripheral portion 820a and a bore peripheral portion 820b that respectively surround the bore peripheral portions 11b and 11c of the cylinder liner 11.

[0137] In this modification as well, the contact member 821 is made of a metal material (for example, a steel plate, a copper alloy, a shape memory alloy, etc.), and has a higher thermal conductivity than the resin material constituting the spacer body member 820 and the cylinder liner 11.

[0138] The water jacket spacer 82 according to this modification is different from the first to fifth embodiments and the first and second modifications in the arrangement of the contact member 821 with respect to the cylinder liner 11, but the other configurations are the same. Therefore, even when the water jacket spacer 82 according to this modification is adopted, the same effects as those of the first to fifth embodiments and the first and second modifications can be obtained.

[0139] Further, in the water jacket spacer 82 according to this modification example, the contact member 821 is fixed to the bore intermediate portion 820l of the spacer body member 820, and the contact member 821 is brought into contact with the bore intermediate portion 11d of the cylinder liner 11 when the engine 8 is driven. Therefore, the heat of the bore intermediate portion 11d that becomes high temperature when the engine 8 is driven can escape to the coolant through the contact member 821. Thus, it is possible to more effectively cool the upper part A1 of the bore (see FIG. 3) when the engine 8 is driven.

[0140] Regarding the arrangement of the contact member 821, it is also possible to combine the arrangement form adopted in this modification example with the arrangement forms adopted in the first to fifth embodiments and modification examples 1 and 2 above.

[0141] Further, regarding the configuration of the contact member 821, it is possible to adopt the same configuration as any of the first to fifth embodiments and modification examples 1 and 2 above, or to adopt a combination thereof.

[0142] [Modification Example 4] The structure of the water jacket spacer 92 according to Modification Example 4 will be described with reference to FIGS. 11(a) and 11(b). FIG. 11(a) is a cross-sectional view showing a partial configuration of an engine 9 in which the water jacket spacer 92 is employed. FIG. 11(b) is a cross-sectional view showing the configuration of the H-H cross-sectional line in FIG. 11(a). In FIGS. 11(a) and 11(b), members having the same configuration as those in the first to fifth embodiments are denoted by the same reference numerals, and the description thereof will be omitted below.

[0143] The water jacket spacer 92 according to the present embodiment is different from the first to fifth embodiments and modification examples 1 to 3 in that the upper extending portion and the lower extending portion 921c of the contact member 921 are arranged obliquely with respect to the flow direction of the coolant in the water jacket 1e.

[0144] Specifically, as shown in Fig. 11(a), the contact member 921 of the water jacket spacer 92 has an upper extension portion 921a, a bending portion 921b, and a lower extension portion 921c, similar to the first embodiment. As shown in Figs. 11(a) and (b), in the contact member 921 of this modification, the angles of the surfaces of the upper extension portion 921a and the lower extension portion 921c are formed to be oblique with respect to the direction of the flow Flow of the coolant.

[0145] Note that the contact member 921 of this modification is also made of a metal material (for example, a steel plate, a copper alloy, a shape memory alloy, etc.) in the same manner as the first embodiment to the fifth embodiment and modification 1 to modification 3.

[0146] The water jacket spacer 92 according to this modification is different from the first embodiment to the fifth embodiment and modification 1 to modification 3 in that the upper extension portion 921a and the lower extension portion 921c in the contact member 921 are configured to be oblique with respect to the direction of the flow Flow of the coolant, but the other configurations are the same. Therefore, even when the water jacket spacer 92 according to this modification is adopted, the same effects as the first embodiment to the fifth embodiment and modification 1 to modification 3 can be obtained.

[0147] Further, in the water jacket spacer 92 according to this modification, since the upper extension portion 921a and the lower extension portion 921c in the contact member 921 are configured to be oblique with respect to the direction of the flow Flow of the coolant, the opposing area to the flow Flow of the coolant can be increased, and the heat dissipation effect can be improved. Therefore, if the water jacket spacer 92 according to this modification is adopted, it is possible to more effectively cool the upper part A1 (see Fig. 3) of the bore when the engine 9 is driven.

[0148] Note that when the contact member 921 of this modification is formed using a shape memory alloy, the upper extension portion 921a and the lower extension portion 921c may be configured to change angles as shown in Figs. 11(a) and (b) only when the temperature of the coolant rises above a predetermined temperature.

[0149] Further, the configuration of the contact member 921 in this modified example can also be combined with the configuration of any one of the fifth embodiment and the first to fourth modified examples from the second embodiment above.

[0150] [Other Modified Examples] In the first to fifth embodiments and the first to fourth modified examples above, the spacer body members 120, 220, 320, 520, 620, 720, and 820 integrally formed using a resin material are adopted. However, in the present invention, it is also possible to adopt a spacer body member configured by combining a plurality of elements.

[0151] Further, in the first to fifth embodiments and the first to fourth modified examples above, the contact members 121, 221, 321, 421, 521, 621, 721, 821, and 921 integrally formed using a metal material are adopted. However, in the present invention, it is also possible to adopt a contact member configured by combining a plurality of elements. For example, in the contact member, when changing the posture from the first posture to the second posture, a thick metal plate may be used for a portion that is not desired to be deformed. Conversely, when taking the second posture, it is also possible to suppress the rigidity of the portion pressed against the cylinder bore wall to be low and increase the contact area.

[0152] Further, in the first to fifth embodiments and the first to fourth modified examples above, the water jacket spacers 12, 22, 32, 42, 52, 62, and 92 are applied to the in-line four-cylinder engines as the engines 1 to 9. However, in the present invention, it is also possible to apply them to a single-cylinder engine, a two-cylinder or three-cylinder engine, or even an engine with five or more cylinders. Also, for the engine type, for example, a V-type or W-type four-cylinder or more engine can also be adopted.

[0153] In addition, in the first to fifth embodiments and the first to fourth modification examples, a configuration in which the cylinder liner 11 is fitted into the cylinder block 10 is adopted. However, the present invention is not limited to this. An engine having a configuration in which a cylinder bore wall is directly provided in the cylinder block can also be adopted.

[0154] In addition, in the first to fifth embodiments and the first to fourth modification examples, the spacer body members 120, 220, 320, 520, 620, 720, 820 are formed using a resin material, and the contact members 121, 221, 321, 421, 521, 621, 721, 821, 921 are formed using a metal material. However, the present invention is not limited to this. As long as the contact member has higher thermal conductivity than the spacer body member and the cylinder liner 11, there is no limitation on the materials used for their respective formations. For example, both the contact member and the spacer body member may be formed using a resin material, or both may be formed using a metal material.

[0155] In addition, if a spacer body member formed using ceramics is adopted, the spacer body member can also have high thermal conductivity by selecting the material, which is advantageous for cooling the engine.

[0156] In addition, in the first to fifth embodiments and the first to fourth modification examples, the contact members 121, 221, 321, 421, 521, 621, 721, 821, 921 are arranged on both the intake side and the exhaust side on the radially outer side of the cylinder liner 11. However, the present invention is not limited to this. For example, the contact member may be arranged only on the exhaust side within the periphery of the cylinder liner (cylinder bore wall) 11. This is because when the engine is running, the upper part of the bore becomes hotter on the exhaust side than on the intake side. Therefore, even if the contact member is arranged only on the exhaust side, which is hotter than the intake side, the temperature of the upper part of the bore can be effectively cooled.

[0157] In addition, in the above-described first to fifth embodiments and the above-described first to fourth modification examples, a metal material such as a steel plate is adopted as the forming material of the contact members 121, 221, 321, 421, 521, 621, 721, 821, 921. Among metal materials, if a copper alloy is adopted, the thermal conductivity is higher than that of each material constituting the cylinder bore wall and the cylinder block. Therefore, it is particularly suitable for transferring the heat at the upper part of the bore to the coolant.

Explanation of Signs

[0158] 1 - 9 Engine 1e Water jacket 10 Cylinder block 10a Inner wall surface 11 Cylinder liner (cylinder bore wall) 11a Outer wall surface 12, 22, 32, 42, 52, 62, 92 Water jacket spacer 120, 220, 320, 520, 620, 720, 820 Spacer body member 120e, 220e, 320e, 520e, 620e Upper wall portion 120f, 220f, 320f, 520f, 620f Lower wall portion 121, 221, 321, 421, 521, 621, 721, 821, 921 Contact member 122, 222, 322, 622 Expansion member A1 Upper part of bore A2 Lower part of bore

Claims

1. A water jacket spacer inserted into a water jacket formed between an outer wall surface of a cylinder bore wall of an engine and an inner wall surface of a cylinder block, when the top dead center side in the cylinder bore of the engine is considered as the top and the bottom dead center side is considered as the bottom, a spacer body member having an upper wall portion closer to the inner wall surface at the upper portion of the water jacket and a lower wall portion connected to the upper wall portion and closer to the inner wall portion at the lower portion of the water jacket, a long contact member having one end fixed to the upper wall portion of the spacer body member, capable of changing its posture between a first posture spaced apart from the outer wall surface and a second posture in contact with the outer wall surface, and having a higher thermal conductivity than the spacer body member and the cylinder bore wall, comprising: the contact member takes the first posture when the water jacket is not filled with a coolant and the engine is not running, and takes the second posture when the water jacket is filled with the coolant and the engine is running, a water jacket spacer structure.

2. further comprising a telescopic member fixed to the other end of the contact member and capable of changing between a state of contraction when the contact member takes the first posture and a state of extension when the contact member takes the second posture, The water jacket spacer structure according to Claim 1.

3. The telescopic member is formed using cellulose sponge or bimetal, The water jacket spacer structure according to Claim 2.

4. The spacer body member further has a connecting wall portion connecting the upper wall portion and the lower wall portion, The connecting wall portion has a through hole allowing the insertion of the contact member, The telescopic member is disposed below the connecting wall portion, The water jacket spacer structure according to Claim 2.

5. The spacer body member further has a connecting wall portion connecting the upper wall portion and the lower wall portion, The telescopic member is disposed on or above the connecting wall portion, The water jacket spacer structure according to Claim 2.

6. The spacer body member is formed using a resin material, The contact member is formed using a metal material, The water jacket spacer structure according to Claim 2.

7. The contact member is configured to change its posture from the first posture to the second posture within the elastic range. The water jacket spacer structure according to claim 6.

8. The contact member is formed using a shape memory alloy, takes the first posture when the temperature of the contact member is less than a predetermined temperature, and is configured to take the second posture when the temperature of the contact member becomes equal to or higher than the predetermined temperature as the temperature of the coolant rises. The water jacket spacer structure according to claim 1.

9. A plurality of the contact members are provided in a circumferentially dispersed state with respect to one cylinder bore wall. The water jacket spacer structure according to any one of claims 1 to 8.

10. The engine is an in-line multi-cylinder engine in which a plurality of cylinder bores are arranged in the cylinder row direction. The contact member is disposed so as to be able to contact a portion between the cylinder bores on the outer wall surface of the cylinder bore wall. The water jacket spacer structure according to any one of claims 1 to 8.

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