JPH0689712B2 - Insulation engine structure - Google Patents

Description

The present invention relates to the structure of an adiabatic engine. Here, the cylinder head liner is a cylinder head lower surface portion and a cylinder liner upper portion that are integrally formed.

[Conventional technology]

Conventionally, engine members such as adiabatic engines using a ceramic material as a heat insulating material or a heat resistant material are disclosed in
-192647 gazette. Tokushikai 59-192647
The cylinder liner of the adiabatic engine disclosed in the publication will be outlined with reference to FIG. The cylinder liner of this adiabatic engine is configured such that the inner diameter of the liner upper portion 28 of the liner head 25 in which the cylinder head inner wall portion 26 and the cylinder liner upper portion 28 are integrally formed is larger than the inner diameter of the cylinder liner 27. Although not shown, it is installed on the cylinder head via an insulating gasket on the outer surface of the liner upper part 28, and therefore, the cylinder liner upper part 28 of the liner head 25 and the piston head 29 do not come into contact with each other and are smooth. A durable operation can be performed. The liner head 25 has a cylinder head inner wall portion 26 and a cylinder liner upper portion 28, which are exposed to the highest temperature / high pressure gas during one cycle of the engine and in which most heat escapes, are integrally formed. . In such a configuration, the hot exhaust gas from the engine drives the exhaust turbine, and the output obtained by the drive causes the exhaust compressor to rotate the intake compressor to supercharge the engine and simultaneously rotate the generator. To generate electricity,
The electric power is used to rotate the electric motor through the controller and reuse the output.

[Problems to be solved by the invention]

However, it is extremely difficult to obtain sufficient heat insulating properties in a heat insulating engine member such as a cylinder head that uses the above ceramics as a heat insulating material or a heat resistant material, and the wall thickness increases in order to obtain sufficient heat insulating characteristics. There is a problem. That is, the part of the engine facing the combustion chamber is made of silicon nitride ceramics, which has excellent heat resistance, heat insulation, and heat shock resistance, and can withstand high-temperature combustion gas. Becomes large, which causes a problem of reduced inhalation efficiency. That is, in the intake process, a large amount of intake air receives heat from the combustion chamber and reaches a high temperature, which reduces the intake efficiency and prevents the air from being taken in. On the other hand, there is a problem that the adiabaticity must be improved in the expansion process. is there. Further, in a diesel engine, fuel is sprayed from the fuel injection nozzle, but the sprayed fuel is rapidly mixed with intake air in the combustion chamber,
Although it is desirable that the swirls are generated in the combustion chamber to uniformly mix them, the present situation is that nothing satisfying this point has been disclosed. By the way
In the cylinder liner of the heat insulation engine disclosed in Japanese Patent Laid-Open No. 59-192647, the liner head 25 including the cylinder head inner wall portion 26 and the upper portion of the cylinder liner is made of a relatively thick ceramic material. Therefore, there is no technical idea that the heat capacity becomes large as in the above case and the heat capacity of the portion exposed to the high temperature is made small, and the same problem as described above occurs.

An object of the present invention is to eliminate the above-mentioned problems, and to obtain a high degree of heat insulation, and to face the combustion chamber side composed of the lower surface of the cylinder head and the upper portion of the cylinder liner that are exposed to combustion gas and become high in temperature. The heat capacity of the cylinder head liner is configured to be as small as possible to improve the intake efficiency and cycle efficiency, and the shape of the combustion chamber is swirled with respect to the fuel spray locus to generate swirl agitation action and sucked into the combustion chamber. The air and the sprayed material are quickly and uniformly mixed and burned, and there is no problem in strength even if a heat shock is received, and heat resistance, deformation resistance, corrosion resistance, etc. are improved, Moreover, it is to provide a structure of an adiabatic engine configured to obtain a stable mounting state.

[Means for solving problems]

The present invention is configured as follows in order to solve the above problems and achieve the above objects. That is, according to the present invention, a cylinder head liner made of a thin ceramic member having an upper portion formed in a square tubular body is coupled to a metal liner via a heat insulating gasket, and the square tubular body of the ceramic member and the metal liner are connected to each other. With regard to the structure of the heat insulation engine, which is characterized in that a heat insulating material such as ceramic fiber is filled between the metal liner and the metal liner, the metal liner is a material having a thermal expansion coefficient substantially equal to that of the ceramic member. Also, the present invention relates to a structure of an adiabatic engine characterized in that an intake / exhaust valve hole and an intake / exhaust valve seat around the same are formed in the longest diameter direction of the lower surface of a rectangular cylinder head.

[Action]

The structure of the heat insulation engine according to the present invention is configured as described above, and operates as follows. That is, according to the present invention, a cylinder head liner made of a thin ceramic member having an upper portion formed in a square tubular body is coupled to a metal liner via a heat insulating gasket, and the square tubular body of the ceramic member and the metal liner are connected to each other. Since a heat insulating material such as a ceramic fiber is filled in the space, the thickness of the ceramic member can be formed as thin as possible due to the presence of the heat insulating gasket, and the heat capacity thereof can be made as small as possible. Further, the upper combustion chamber formed by the ceramic member has a shape of the square tube body, and swirls generated in the combustion chamber are broken by the sides of the square tube body to generate a stirring action in the swirl and are sprayed. The fuel and the intake air are mixed very quickly, that is, near the top dead center and evenly during the moment, and the combustion is satisfactorily performed. That is, the thinner the thickness of the ceramic member forming the combustion chamber is, the better the followability to the gas temperature in the combustion chamber is, and the wall temperature amplitude between the high temperature and the low temperature in the combustion chamber is thicker. Is thicker than when thick,
As a result, the temperature difference between the combustion gas and the ceramic member on the wall surface of the combustion chamber becomes small, the heat transfer amount decreases, and the heat reception of the income air decreases, so that the suction efficiency does not decrease.

〔Example〕

Hereinafter, embodiments of the structure of the heat insulation engine according to the present invention will be described in detail with reference to the drawings.

1 and 2, the structure of an adiabatic engine according to an embodiment of the present invention is generally indicated by reference numeral 10. 1 is a sectional view taken along line I-I in FIG. 2, and FIG. 2 is a sectional view taken along line II-II in FIG.
The structure 10 of this heat insulating engine relates to the heat insulating structure of the heat insulating cylinder head liner itself, and mainly includes a cylinder head liner, that is, a ceramic member 1, a ceramic material 1 and a heat insulating material which are integrally formed by combining the cylinder liner upper portion 2 and the cylinder head lower surface portion 4. Expansion coefficient, in other words, materials having the same linear expansion coefficient, for example, a heat resistant alloy such as a nickel-chrome alloy, a metal liner 3 made of stainless steel, and a heat insulating material arranged between the ceramic member 1 and the metal liner 3. 6 and a heat insulating gasket 8. The ceramic member 1 is a thin-walled cylinder head liner that forms the combustion chamber 5, and a step 12 is formed in the middle thereof.
And the cylinder liner upper portion 2 above the step portion 12 is formed in the rectangular cylindrical body 7 (see in particular FIG. 2), and the cylinder liner upper portion 2 below the step portion 12 is formed in the cylindrical body 13. It is a thing. In addition, the ceramic member 1 and the metal liner 3 may be connected to each other at their lower ends by a packing 14 made of, for example, copper and a heat insulating material, as shown in the figure, so that the ceramic member 1 with respect to the metal liner 3 is The positioning can be ensured and the sealing property can be improved. By the way, a space above the stepped portion 12 of the ceramic member 1 is formed between the cylinder liner upper portion 2 of the ceramic member 1 and the metal liner 3, and the space is made of a ceramic fiber or the like. The heat insulating material 6 is poured and molded. By interposing the heat insulating material 6 between the cylinder liner upper portion 2 and the metal liner 3, the heat insulating effect can be further enhanced. Furthermore, regarding the cylinder head lower surface portion 4 which constitutes the fire deck portion,
The cylinder head is formed in a rectangular shape, and intake / exhaust holes 11 and 11 'and intake / exhaust valve seats 9 and 9' around the intake / exhaust holes 11 and 11 'are formed in the direction of the longest diameter of the cylinder head lower surface portion 4. The portion of the ceramic member 1 on which the intake / exhaust valve seats 9 and 9'are formed is structured so that the strength of that portion is stronger than the strength of the other portions. In some cases, the intake / exhaust valve seat may be configured so that the intake / exhaust valve 15 can be received by the metal liner.

In the structure of the heat insulating engine thus constructed, that is, the heat insulating cylinder head liner, the heat can be effectively cut off particularly during a period of heat generation during active combustion. Ceramic member 1 of the cylinder head liner having such a shape
The combustion chamber 5 formed by can be configured in a shape most suitable for a combustion chamber of an adiabatic engine.
That is, regarding the shape of the combustion chamber 5, as shown in FIG. 2, a part of the upper portion 2 of the cylinder liner is formed into a quadrangular cylinder 7 having a rectangular cross section, and the lower portion has a round cross section, that is, a cylindrical body 13.
Is formed in. Further, it is preferable in terms of fluid flow that the square tubular body 7 has a corner portion formed into a curved surface, for example, a curved surface having a radius of about 1/2 to 2/3. With such a shape, the swirl generated in the combustion chamber 5 is broken by the sides of the rectangular cylindrical body 7, that is, the gas vortex is broken to generate a stirring action, and the sprayed fuel and the intake air are extremely quickly, that is, the upper part. The mixture is uniformly mixed in the vicinity of the dead point during the moment, and the combustion is performed well. Further, since the outer peripheral surface of the cylinder head liner, that is, the cylinder liner upper portion 2 of the ceramic member 1 is insulated by the heat insulating gasket 8 and the heat insulating material 6 such as potassium titanate, the ceramic member 1 itself should be thin. Therefore, the heat capacity can be reduced. The combustion chamber 5 is inside the rectangular tubular body 7 from the step portion 12 to the upper portion in the drawing, and the space 16 formed with the piston upper surface is configured to have an efficient and minimum heat transfer area.

The heat insulating material 6 is made of a ceramic fiber made of a mixture with potassium titanate whiskers, alumina fibers, or the like, and in some cases, a heat insulating air layer can be formed in the ceramic fiber. As for the heat insulating gasket 8 which is a heat insulating material, for example, one in which potassium titanate paper is laminated, one in which an organic binder is mixed with potassium titanate whiskers, and which is integrally formed,
Alternatively, there are those obtained by mixing potassium titanate whiskers, alumina fibers, and an organic binder and molding them.
In addition, as examples of these heat insulating materials, ceramic sheets impregnated with potassium titanate are laminated, that is, laminated, or an organic binder containing potassium titanate whiskers as a main component is mixed to form a paper form. A laminated sheet of sheets, a sheet of a sheet formed by mixing an organic binder containing potassium titanate whiskers as a main component with an organic binder and reinforced by sandwiching the upper and lower surfaces with alumina fiber sheets, potassium titanate Not limited to those obtained by mixing and molding alumina fibers, which are alumina short fibers containing whiskers as a main component, and an organic binder, or potassium titanate whiskers, ceramic fibers such as zirconia fibers may be used, and heat insulating material 6 and For the heat insulating gasket 8, select the above heat insulating material appropriately It can be fabricated Te.

〔The invention's effect〕

Since the structure of the heat insulation engine according to the present invention is configured as described above, it has the following unique effects. That is, according to the present invention, a cylinder head liner made of a thin ceramic member having an upper portion formed in a square tubular body is coupled to a metal liner via a heat insulating gasket, and the square tubular body of the ceramic member and the metal liner are connected to each other. Since a heat insulating material such as a ceramic fiber is filled in between, the thickness of the ceramic member which is exposed to the combustion gas and becomes high temperature due to the presence of the heat insulating gasket can be formed as thin as possible, and its heat capacity can be made as small as possible. The structure is extremely preferable because it can be made extremely small, high degree of heat insulation can be obtained, deformation resistance, heat resistance, and corrosion resistance are excellent. Further, the shape of the rectangular cylindrical body of the ceramic member causes a stirring action, so that the atomized fuel and the intake air are mixed very quickly, that is, evenly in the vicinity of the top dead center in an instant, and combustion is excellent. Done. Since the thickness of the ceramic member forming the combustion chamber can be made as thin as possible, the amount of heat received by heat transfer is reduced, so that the thermal expansion of inflowing intake air is reduced and the intake efficiency is not reduced. Further, there is no problem in strength even if it receives a heat shock, heat resistance is improved, and a stable mounting state can be obtained.
Furthermore, the heat insulating material and the heat insulating gasket perform a high-performance heat insulating function with respect to the combustion chamber of the engine, there is no outflow of heat energy from the combustion chamber through the piston, and heat energy is exhausted from the combustion chamber to the exhaust port. Through to the energy recovery device installed downstream, so that the energy recovery device can effectively recover the thermal energy of the engine and reuse the thermal energy.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the structure of an adiabatic engine according to the present invention, FIG. 2 is a sectional view taken along the line II-II in FIG. 1, and FIG. 3 is an example of a cylinder liner of a conventional adiabatic engine. FIG. 1 ... Ceramic member, 2 ... Upper part of cylinder liner, 3
…… Metal liner, 4 …… Cylinder head bottom surface, 5…
… Combustion chamber, 6… Insulation, 7 …… Square cylinder, 8 …… Insulation gasket, 9,9 ′ …… Intake / exhaust valve seat, 10 …… Insulation engine structure, 11,11 ′ …… Intake / exhaust Port, 12 ……
Step, 13 …… Cylinder, 14 …… Metal packing.

Claims (3)

[Claims] 1. A cylinder head liner made of a thin ceramic member having an upper portion formed in a square tubular shape is attached to a metal liner via a heat insulating gasket, and between the square tubular body of the ceramic member and the metal liner. The structure of the heat insulation engine is characterized in that the heat insulation material is interposed in the structure. 2. The structure of the heat insulation engine according to claim 1, wherein the metal liner is made of a material having a coefficient of linear expansion substantially equal to that of the ceramic member. 3. The structure of an adiabatic engine according to claim 1, wherein an intake / exhaust valve seat is formed in the direction of the longest diameter of the lower surface of the rectangular cylinder head of the cylinder head liner.