JPH0332765Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Technical field of the invention The present invention relates to a seal structure for a combustion chamber in an internal combustion engine such as an automobile.

(b) Background of the technology The engine body of automobiles etc. consists of cylinder heads,
It consists of a cylinder block, a cylinder liner, etc. A combustion chamber is formed by the cylinder head and the cylinder liner, and a piston is inserted into the combustion chamber. Since the combustion chamber is at high temperature and pressure, a gasket is interposed between the cylinder head and the cylinder block to prevent combustion gas from leaking. However, since this gasket is constantly exposed to a high temperature and high pressure atmosphere, it deteriorates due to the heat generated within the combustion chamber, resulting in a problem that the sealing performance is impaired.

(c) Prior Art and Problems FIG. 2 shows a conventional combustion chamber seal structure described in Japanese Utility Model Application Publication No. 157356/1983. In this figure, 1 is a cylinder block, and a packing 5 is interposed between a cylinder liner 2 and a cylinder head 3 as a gasket. A circumferential groove 6 is formed in the upper end surface 2a of the cylinder liner 2, and a spring 8 and a seal ring 7 are inserted into the circumferential groove 6. Seal ring 7
is urged toward the cylinder head 3 by the spring 8,
The upper surface 7c of the seal ring 7 is in close contact with the lower surface 3a of the cylinder head 3.

In the case of the engine with the above configuration, the seal ring 7 blocks the heat generated in the combustion chamber 4 from being transmitted to the gasket 5 side.
can be prevented from deteriorating due to heat.

However, when the inner wall surface of the cylinder liner 2 deforms at high temperatures, the elastic force of the spring 8 alone cannot sufficiently press the seal ring 7, causing the upper surface 7c of the seal ring 7 and the lower surface 3a of the cylinder head 3 to A gap was created, and there was a possibility that deterioration of the packing 5 due to heat could not be sufficiently suppressed.

Further, carbon contained in the exhaust gas may adhere to the circumferential groove 6, and in such a case, the movement of the sealing 7 is slowed by the carbon, and the relationship between the sealing 7 and the lower surface 3a of the cylinder head 3 is reduced. Adhesion was lost, and from this point of view as well, there was a risk that deterioration of the gasket 5 due to heat could not be sufficiently suppressed.

(d) Purpose of the invention The present invention was made in view of the above, and its purpose is to prevent carbon from adhering to the annular groove formed in the top end face of the cylinder liner, even if the cylinder liner is deformed at high temperatures. An object of the present invention is to provide a sealing structure for a combustion chamber in an internal combustion engine that can sufficiently suppress thermal deterioration of a gasket.

(E) Structure of the invention In order to achieve the above object, the present invention includes a gasket interposed between the cylinder block and the cylinder head, an annular groove formed in the top end surface of the cylinder liner, and a seal installed in the annular groove. In the combustion chamber sealing structure of an internal combustion engine equipped with the member, the annular groove is formed into a groove whose bottom part gradually becomes smaller in diameter than the open end, a temperature-sensitive member is fitted to the bottom side of the annular groove, and a temperature-sensitive member is fitted to the upper side of the annular groove. This device is characterized by being equipped with a sealing member that moves as the heating member expands and contracts.

(c) Embodiment of the invention Hereinafter, a preferred embodiment of the invention will be described based on FIG. 1.

In the figure, 1 is a cylinder block, 2 is a cylinder liner, and 3 is a cylinder head. The cylinder liner 2 and the cylinder head 3 form a combustion chamber 4.
is formed. A gasket 5 is interposed between the cylinder head 3 and the cylinder block 1. Further, an annular groove 10 is formed in the top end face of the cylinder liner 2 on the cylinder head 3 side, which is closer to the combustion chamber 4 than the gasket 5 is. This annular groove 10 extends from the open end 10a to the bottom 1.
It is formed so that the diameter becomes gradually smaller on the 0b side.
A temperature-sensitive member 12 that expands (expands and contracts) in response to temperature is inserted into the bottom portion 10b of the annular groove 10 and is made of a material with a high coefficient of thermal expansion, for example, heat-resistant steel. A combustion chamber 4 is located above this temperature sensing member 12.
When the temperature reaches a high temperature, the temperature sensing member 12 expands and moves toward the cylinder head 3, and an annular seal member 18 is inserted to block the heat conduction path 16 that leads the heat in the combustion chamber 4 to the gasket 5 side. has been done. The seal member 18 is made of ceramics.

In the above configuration, when the inside of the combustion chamber 4 is at a low temperature, the seal between the cylinder head 3 and the cylinder block 1 is provided by the gasket 5, and the heat of the cylinder head 3, cylinder block 1, cylinder liner 2, etc. The gasket 5 suppresses deformation of the engine body due to expansion.

On the other hand, when the inside of the combustion chamber 4 becomes high temperature, the temperature sensing member 12 expands, the seal member 18 moves toward the cylinder head 3, and the conduction path 16 is connected to the seal member 1.
8. Therefore, the sealing member 18 prevents the high heat in the combustion chamber 4 from being transmitted to the gasket 5.
Therefore, thermal deterioration of the gasket 5 can be sufficiently suppressed.

Furthermore, in this embodiment, since the annular groove 10 has a larger diameter on the open end 10a side than on the bottom 10b side, even if the cylinder liner 2 is deformed, the temperature sensing member 1
2, the sealing member 18 can be reliably moved toward the cylinder head 3. Alternatively, even if carbon contained in the exhaust gas adheres to the inside of the annular groove 10, it is pushed out by the movement of the seal member 18, and the seal member 18 reliably contacts the cylinder head 3, thereby preventing thermal deterioration of the gasket 5. can be sufficiently suppressed.

(g) Effects of the invention As explained above, the invention includes a gasket interposed between the cylinder block and the cylinder head, an annular groove formed in the top end face of the cylinder liner, and a sealing member installed in the annular groove. In the combustion chamber seal structure of an internal combustion engine, the annular groove is
The cylinder liner is deformed by making the groove gradually smaller in diameter at the bottom than at the open end, fitting a temperature sensing member into the bottom side of the annular groove, and installing a sealing member on the top side that moves as the temperature sensing member expands and contracts. Even if carbon is deposited inside the annular groove, the expansion of the temperature-sensitive member will ensure that the sealing member moves toward the cylinder head, and the movement of the sealing member will eliminate the carbon deposited inside the annular groove. is pushed out, the sealing member reliably comes into close contact with the cylinder head, and thermal deterioration of the gasket can be sufficiently suppressed.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a main part of a combustion chamber showing an embodiment of the present invention, and FIG. 2 is a vertical cross-sectional view of a conventional combustion chamber. 1... Cylinder block, 2... Cylinder liner, 3... Cylinder head, 4... Combustion chamber, 5...
... Gasket, 10 ... Annular groove, 12 ... Temperature-sensitive member, 18 ... Seal member.

Claims (1)

[Scope of utility model registration request] In a combustion chamber sealing structure for an internal combustion engine, a gasket is interposed between a cylinder block and a cylinder head, an annular groove is bored in the top end face of a cylinder liner, and a sealing member is installed in the annular groove. An internal combustion engine characterized by having a groove whose diameter gradually becomes smaller at the bottom than the open end, a temperature sensing member fitted to the bottom side of the annular groove, and a sealing member which moves as the temperature sensing member expands and contracts installed at the top side. Seal structure of combustion chamber in engine.