JP2012031752A - Heat insulating structure of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique that is also applied to a part where a thin-film heat insulating material is required, in a heat insulating structure that is attached to a structural member of an internal combustion engine.SOLUTION: The structure includes: the heat insulating material 3 which connects to a plurality of porous materials; and an organic material 40 which has heating and disappearing characteristics and which is impregnated with the heat insulating material 3. The structure is also designed to be joined to the structural member 20 of the internal combustion engine via the organic material 40. The heat insulating structure 10 burns down the organic material 40 positioned on a surface of the heat insulating structure 10, and remains the organic material 40 positioned adjacent to a joint surface between the structural member 20 and itself without burning down it. As a result, the heat insulating structure 10 makes the thickness thereof thin without deteriorating a joining state between the heat insulating structure 10 and the structural member 20.

Description

  The present invention relates to a heat insulating structure joined to a structural member of an internal combustion engine.

  In an internal combustion engine mounted on an automobile or the like, a heat insulating material may be provided for the purpose of improving the heat resistance of a structural member or reducing cooling loss. By the way, when a heat insulating material and a structural member are directly joined, peeling or the like may occur at the joining interface between them. For such a problem, a method of joining a heat insulating material and a structural member via a porous material impregnated with an adhesive has been proposed (see, for example, Patent Document 1).

JP 2009-257104 A

  By the way, according to the above-described method, since the thickness is increased by a member interposed between the heat insulating material and the structural member, there is a possibility that the thin film heat insulating material cannot be applied to a necessary place.

  The present invention has been made in view of various circumstances as described above, and an object of the present invention is to provide a technique that can be applied to a place where a thin-film heat insulating material is required in a heat insulating structure of an internal combustion engine. .

  In order to solve the above-described problems, the present invention is made to impregnate a porous heat insulating material with an organic material and to bond the heat insulating material to a structural member of the internal combustion engine via the organic material.

In detail, the heat insulating structure of the internal combustion engine according to the present invention is:
A heat insulating material in which a plurality of porous materials are connected;
An organic material having heat dissipation properties and impregnated in the heat insulating material;
Including
It was made to join to the structural member of the internal combustion engine through the organic material.

  According to the heat insulation structure of the internal combustion engine configured as described above, the organic material located on the surface of the heat insulation structure disappears in response to heat generated by the internal combustion engine. As a result, the heat insulating material located near the surface of the heat insulating structure is exposed, and the heat insulating function is activated.

  Further, in the heat insulation structure, the organic material located in the part away from the surface of the heat insulation structure, particularly in the vicinity of the joint surface with the structural member, escapes from the heat due to the heat insulation action of the exposed heat insulation material, and thus remains without disappearing. To do. As a result, the joined state between the heat insulating structure and the structural member is maintained. Furthermore, since the thermal expansion difference between the heat insulating material and the structural member is attenuated by the organic material, peeling of the bonding interface is also suppressed.

  Therefore, according to the heat insulating structure of the internal combustion engine according to the present invention, it is possible to suppress the thickness of the heat insulating structure while suppressing deterioration of the bonding state between the heat insulating structure and the structural member. As a result, the heat insulating structure of the present invention can be applied to a place where a thin film heat insulating material is required.

  As the organic material of the present invention, an organic material having a higher thermal conductivity than the heat insulating material can be used. In that case, the organic material disappears uniformly on the surface of the heat insulating structure. As a result, the exposure degree of the heat insulating material can be made uniform on the surface of the heat insulating structure.

  In the present invention, the structural member to which the heat insulating structure is joined may be a resin molded material or a metal. When the structural member is a metal, an organic adhesive can be used as the organic material according to the present invention. In that case, the thickness of the heat insulating structure can be suppressed while suppressing the deterioration of the bonding state between the heat insulating structure and the metal structural member.

  Moreover, as a structural member to which the heat insulation structure of this invention is joined, the structural member cooled with the cooling water of an internal combustion engine is desirable. This is because if the heat generated by the internal combustion engine, particularly the heat generated when the fuel burns, is radiated to the cooling water, the cooling loss tends to increase.

  In the present invention, the thickness of the heat insulating material impregnated with the organic material (the thickness of the portion excluding the portion where the heat disappears) is the minimum value within a range in which the difference in thermal expansion between the heat insulating material and the metal structural member can be absorbed. It may be set as described above. In that case, the thickness of the heat insulating structure can be made as thin as possible within a range in which the bonding state between the heat insulating structure and the metal structural member does not deteriorate.

  According to the heat insulating structure of the internal combustion engine of the present invention, it is possible to suppress the thickness of the heat insulating structure while suppressing deterioration of the joined state between the heat insulating structure and the structural member. As a result, the heat insulating structure of the internal combustion engine of the present invention can be applied to a place where a thin film heat insulating material is required.

It is a figure which shows the structure of the heat insulation structure at the time of unused in a 1st Example. It is a figure which shows the structure of the heat insulation structure at the time of use in a 1st Example. It is a figure which shows the structure of the heat insulation structure at the time of unused in a 2nd Example. It is a figure which shows the structure of the heat insulation structure at the time of use in a 2nd Example.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. The dimensions, materials, shapes, relative arrangements, and the like of the components described in the present embodiment are not intended to limit the technical scope of the invention to those unless otherwise specified.

<Example 1>
First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows the structure of the heat insulation structure when not in use (new state), and FIG. 2 shows the structure of the heat insulation structure when in use. In addition, a present Example describes the case where a heat insulation structure is applied to a resin-made structural member (resin molding).

  1 and 2, the heat insulating structure 1 is integrally formed with a resin structural member 2. The heat insulating structure 1 is formed of a heat insulating material 3 in which a plurality of porous materials are connected by a bonding medium having high heat resistance, and an organic resin 4 that is impregnated in the heat insulating material 3 and covers the heat insulating material 3. ing. In addition, as the porous material forming the heat insulating material 3, ceramic or the like can be used. As the organic resin 4, a synthetic resin mainly containing H or C can be used. The structural member 2 may be formed of a resin having the same property as the organic resin 4 of the heat insulating structure 1 or may be formed of a resin having a property different from that of the organic resin 4.

The above-described heat insulating structure 1 is molded with the heat insulating material 3 immersed in the organic resin 4. In addition, when the structural member 2 is shape | molded with resin of the same property as the organic resin 4, the heat insulating material 3 is contained in resin.
The heat insulating structure 1 and the structural member 2 may be integrally molded in a state in which is immersed.

  When the heat insulating structure 1 configured as described above is attached to the internal combustion engine, the surface of the heat insulating structure 1 is heated by the heat generated by the internal combustion engine. In that case, the organic resin 4 located on the surface of the heat insulating structure 1 is burned out. As a result, as shown in FIG. 2, the heat insulating material 3 located near the surface of the heat insulating structure 1 is exposed.

  As shown in FIG. 2, when the heat insulating material 3 near the surface of the heat insulating structure 1 is exposed, the heat insulating function of the heat insulating structure 1 is activated. As a result, the amount of heat transferred to the structural member 2 can be reduced. Furthermore, the exposed heat insulating material 3 also reduces the amount of heat transmitted to the organic resin 4 located in the vicinity of the joint portion (see the broken line in FIGS. 1 and 2) of the heat insulating structure 1 with the structural member 2. Therefore, the organic resin 4 located in the vicinity of the above-described joining portion remains without disappearing. As a result, the bonding state between the heat insulating structure 1 and the structural member 2 is appropriately maintained.

  Therefore, according to the present Example, the thickness of the heat insulation structure 1 can be suppressed, suppressing the deterioration of the joining state of the heat insulation structure 1 and the structural member 2. FIG. Therefore, it becomes possible to apply the heat insulation structure 1 of a present Example to the location where a thin film heat insulating material is required.

<Example 2>
Next, a second embodiment of the present invention will be described with reference to FIGS. Here, a configuration different from that of the first embodiment will be described, and description of the same configuration will be omitted.

  The difference between the first embodiment described above and this embodiment is that the heat insulating structure is joined to a metal structural member. FIG. 3 shows the structure of the heat insulating structure when not in use, and FIG. 4 shows the structure of the heat insulating structure when in use.

  3 and 4, the heat insulating structure 10 is joined to a metal structural member 20. The heat insulating structure 10 is formed of a heat insulating material 3 in which a plurality of porous materials are connected by a bonding medium having high heat resistance, and an organic adhesive 40 impregnated in the heat insulating material 3. As the organic adhesive 40, an adhesive mainly composed of H or C can be used. At that time, the component of the organic adhesive 40 is preferably determined so that the Young's modulus of the organic adhesive 40 falls within the range of 1/100 to 1/20 of the Young's modulus of the heat insulating material 3. . Further, the heat insulating structure 10 and the structural member 20 are joined by the organic adhesive 40 described above.

  The heat insulating structure 10 described above is molded by impregnating the heat insulating material 3 with the organic adhesive 40. The heat insulating structure 10 and the structural member 20 are joined by solidifying the organic adhesive 40 in a state where the heat insulating material 3 impregnated with the organic adhesive 40 is fixed to the structural member 20. .

  When the heat insulating structure 10 configured as described above is attached to the internal combustion engine, the surface of the heat insulating structure 10 is heated by the heat generated by the internal combustion engine. In that case, the organic adhesive 40 located on the surface of the heat insulating structure 10 is burned away. As a result, as shown in FIG. 4, the heat insulating material 3 located near the surface of the heat insulating structure 10 is exposed.

  As shown in FIG. 4, when the heat insulating material 3 near the surface of the heat insulating structure 10 is exposed, the heat insulating function of the heat insulating structure 10 works. As a result, the amount of heat transferred to the structural member 20 can be reduced. Furthermore, the exposed heat insulating material 3 also reduces the amount of heat transferred to the organic adhesive 40 located in the vicinity of the joint portion of the heat insulating structure 10 with the structural member 20. Therefore, the organic adhesive 40 located in the vicinity of the joint portion described above remains without disappearing. As a result, the bonding state between the heat insulating structure 10 and the structural member 20 is appropriately maintained.

  By the way, the thermal expansion coefficient of the heat insulation structure 10 (heat insulation material 3) and the structural member 20 are different. Therefore, after the organic adhesive 40 located on the surface of the heat insulating structure 10 disappears, the thickness of the portion impregnated with the organic adhesive 40 (t in FIG. 4) is the same as the structure of the heat insulating structure 10. It is preferable that a thickness obtained by adding a predetermined margin to the minimum thickness tmin that can absorb the thermal expansion difference from the member 20 is preferable. The minimum thickness tmin described above can be calculated by the following equation.

tmin = D * (E ₂ / E ₁ ) * (α ₀ −α ₁ ) * ΔT
In said formula, D is the length (D in FIG. 4) of the joint surface of the heat insulation structure 10 and the structural member 20. As shown in FIG. E ₁ and E ₂ are Young's moduli of the heat insulating material 3 and the organic adhesive 40, respectively. α _{0 and} α ₁ are the thermal expansion coefficients of the structural member 20 and the heat insulating material 3, respectively. ΔT is the amount of temperature change at the bonding interface.

  When the minimum thickness tmin is obtained, the thickness tb of the disappearing portion and the margin tm are added to the minimum thickness tmin, so that an appropriate thickness of the heat insulating structure 10 when new can be obtained. Further, the material of the heat insulating material 3 and the properties of the organic adhesive 40 are determined so that the ratio of the thickness t to the length D of the joint surface falls within a range of 1/100 to 1/10. Also good.

  When the thickness of the heat insulating structure 10 is determined in this way, the thickness of the heat insulating structure 10 can be made as thin as possible within a range where the bonded state between the heat insulating structure 10 and the structural member 20 does not deteriorate. it can. As a result, the heat insulating structure 10 in the present embodiment can be attached to the top surface of the piston forming the combustion chamber of the internal combustion engine, the inner wall surface of the cylinder head, the valve body of the valve, or the like. In such a case, the heat generated when the fuel burns in the combustion chamber is not easily dissipated to the cooling water, so that it is possible to reduce the cooling loss of the internal combustion engine.

DESCRIPTION OF SYMBOLS 1 Thermal insulation structure 2 Structural member 3 Thermal insulation material 4 Organic resin 10 Thermal insulation structure 20 Structural member 40 Organic adhesive

Claims (6)

A heat insulating material in which a plurality of porous materials are connected;
An organic material having heat dissipation properties and impregnated in the heat insulating material;
Including
The heat insulation structure of the internal combustion engine joined to the structural member of the internal combustion engine through the organic material.   2. The heat insulating structure for an internal combustion engine according to claim 1, wherein the organic material has a thermal conductivity higher than that of the heat insulating material.   3. The heat insulating structure for an internal combustion engine according to claim 1, wherein the structural member is a resin molding material. In Claim 1 or 2, the structural member is a metal forming material,
The organic material is a heat insulating structure of an internal combustion engine which is an organic adhesive.   5. The heat insulating structure for an internal combustion engine according to claim 1, wherein the structural member is a member that is cooled by cooling water of the internal combustion engine.   5. The heat insulating structure for an internal combustion engine according to claim 4, wherein the thickness of the heat insulating material impregnated with the organic material is set to be equal to or greater than a minimum value in a range in which a difference in thermal expansion between the heat insulating material and the metal can be absorbed.

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