JPS6166849A - Ceramics heat insulating engine - Google Patents

Abstract

PURPOSE:To restrain combustion gas from blowing through a clearance between a cylinder liner and a cylinder body with simple and inexpensive constitution, by fitting a seal member in space between the cylinder body and the cylinder liner. CONSTITUTION:The outer circumferential side of a lower end face 4b of a cylinder liner 4 is obliquely chamfered, while a lower end part of a cylindrical surface 20 of a cylinder body 2 is also chamfered whereby a V-shaped groove is formed between them. And, a seal member in the specified sectional formis fitted in the groove, while an annular keep plate 31 is pressed to a lower end face of a wall part forming the cylindrical surface of the cylinder body 2 and clamped with a bolt 32. With this constitution, combusion gas is completely preventable from blowing into a crankcase through a clearance between the cylinder liner 4 and the cylindrical surface 20 to be produced by thermal deformation. And, an expected aim is achievable with simple and inexpensive constitution without entailing any change in the conventional main part.

Description

[Detailed Description of the Invention] [Field of Application of Rakudo] The present invention is applied to an insulation engine using ceramics.

[Conventional technology] Ceramics, which can withstand high temperatures and have excellent heat insulation effects, are used for the combustion chamber wall of the engine to improve thermal cycle efficiency, and also to generate energy by sending high-temperature exhaust gas to the exhaust turbine. A WIT heat engine has already been proposed that can improve the overall thermal efficiency by recovering the heat, but it has not yet reached the stage of practical use due to various problems.

As an lI7+ heat engine for this scale, for example, one shown in FIG. 3 is known. This has a cylinder head 1 made of ordinary metal with a cylindrical part 1a, into which a cup-shaped headliner 3 made of ceramics is fitted via a pair of upper and lower positioning rings 12, and the cylinder head 1 A heat insulating gasket 16 is interposed between the lower surface 1b and the helad liner 3. l for the upper end type of headliner 3! ! A u (exhaust) boat 8 is formed and is opened and closed by an intake (exhaust) valve 7 also made of ceramics. In this way, most of the combustion chamber is divided by the cup-shaped helad liner 3 made of ceramic and the crown part 5 of the piston 26 made of ceramic, and the headliner 3 is separated from the main part of the combustion chamber by the cylinder. It is butted against liner 4.

In reality, in order to avoid stress due to the difference in thermal expansion between the headliner 3 and cylinder liner 4, there is a very small gap between the liners 3 and 4. A seal member 17 is interposed between the body r3 and the upper end surface 4a, and is fastened by screwing bolts from the cylinder head 1 to the cylinder body 2. A cylinder liner 4 is fitted onto the cylindrical surface 20 of the cylinder body 2. Cooling oil chambers 21 and 22 are provided in the cylinder body 2 as necessary.

The piston 26 has a crown part 5 made of ceramics and a skirt part 6 made of gold 5 with a neck through the bolt 11 and the nut 1.
It is composed by combining 3. A depression 9 is provided on the upper end surface of the crown portion 5 to promote mixing of fuel and air, and a protrusion 10 is provided along the outer periphery of the lower end.

Piston rings 41 and 42 are mounted on the skirt portion 6, and a cylindrical portion 14 is formed on the outer periphery of the upper end, into which the protrusion 10 of the crown portion 5 described above is fitted. Further, a protrusion 15 is formed at the center of the upper end of the skirt portion 6, on which the crown portion 5 is placed, and a bolt 11 passing through both as described above.
The nut 13 is screwed onto the holder.

In this adiabatic engine, most of the fuel combustion period takes place in the space surrounded by the headliner 3 and the crown part 5, and the abutting part of the headliner 3 and cylinder liner 4 is where the combustion gas is slightly below the hot water temperature. Place it on the degraded area! 11ff
Therefore, it is possible to reduce the leakage of combustion gas in the a4a pressure state from the abutting portion of the two, and to reduce the thermal load on the seal member 17.

The ceramic used for the headliner 3 is silicon nitride (3i 3 N4), the cylinder liner 4 is made of commonly used cast iron or silicon nitride, which has a low thermal transfer F# ratio, and the piston crown 5 is made of silicon nitride (3i 3 N4). Silicon is used in each case.

[Problem to be Solved by the Invention 1] By the way, as described above, the sealing member 17 is interposed between the headliner 3 and the cylinder body 2 so that the headliner 3 and the cylinder liner 4 do not directly abut each other. In this structure, there is a possibility that combustion gas in the combustion chamber may be blown into the crankshaft through the gap between the cylindrical surface 2o of the cylinder body 2 and the outer peripheral surface of the cylinder liner 4. In other words, if there is a slight gap between the cylinder body 2 and cylinder liner 4 where they fit together due to the difference in thermal expansion coefficient between them, combustion gas will flow through the gap between the lower end of the headliner 3 and the upper end of the cylinder liner 4. The gas blows through the gap between the cylinder liner 4 and the cylindrical surface 20 to the crankshaft, increasing the internal pressure of the crankshaft and generating a large amount of blow-by gas.

Here, if the headliner 3 is directly brought into strong contact with the upper end surface of the cylinder liner 4, this problem can be solved, but
In that case, there is a risk that the headliner 3 or cylinder liner 4 may crack due to thermal stress.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a ceramic insulation engine that can suppress combustion gas from blowing through from a combustion chamber through a gap between a cylinder liner and a cylinder body with a simple structure without making any changes to the conventional configuration. There is a particular thing.

[Means for Solving the Problems] In order to achieve the above object, the present invention has a structure in which a seal member is fitted between the cylinder body and the lower end of the cylinder liner.

[Operation] The cylindrical surfaces of the cylinder liner 4 and the cylinder body 2 are formed through a small gap provided between the lower end of the headliner 3 and the upper end of the cylinder liner 4 to avoid thermal damage caused by collision between them. Even if combustion gas from the combustion chamber flows into the gap between the cylinder liner 4 and the cylinder body 2,
A sealing member 33 installed between the crank and the crankshaft is prevented from blowing to the crank.

[Examples of the Invention] The present invention will be described based on Examples. As shown in FIG. 1, the present invention obliquely chamfers the outer peripheral side of the lower end surface 4b of the cylinder liner 4, and similarly chamfers the lower end of the cylindrical surface 20 of the cylinder body 2 to create a gap between the two. A sealing member 33 having a predetermined cross section is fitted into this groove, and an annular retaining plate 31 is attached to the cylindrical surface 20 of the cylinder body 2.
It is fastened with a pressing bolt 32 to the lower end surface of the wall forming the wall. As shown in FIG. 3, this holding plate 31 has an approximately elliptical outer shape in relation to the adjacent cylinders, and has holes 35 on both sides through which four bolts 32 are inserted.
is provided.

By the time the combustion gas reaches the lower end of the cylinder liner 4,
Since this temperature drops considerably, the annular sealing member 33
The material may be commonly used rubber, synthetic resin, metal, etc., but fluorine rubber, stainless steel, Inconel, etc., which have excellent heat resistance, are preferable.

[Effect between lights] As described above, the present invention forms a ■-shaped groove between the cylinder body 2 and the cylinder liner 4 fitted to the cylindrical surface 20 at the lower end thereof, and Since the sealing member 33 is engaged with the holding plate 31, combustion gas can be completely prevented from blowing through to the crank through the gap between the cylinder liner 4 and the cylindrical surface 20 caused by thermal deformation. It is possible to configure the conventional main part without any change, and the sealing member 3
Since the thermal angle load of No. 3 is small, common materials can be used as the sealing member, which reduces the cost increase.
I can do it by keeping it down to

[Brief explanation of drawings]

Fig. 1 is a front cross-sectional view showing the main parts of a ceramic heat-insulated engine according to the present invention, Fig. 2 is a plan view of a presser plate that couples the seal portion of the engine, and Fig. 3 is a flash structure of the ceramic heat-insulated engine. FIG. 1 Niji cylinder head 2 Niji cylinder body 3: Helad liner 4 Niji cylinder liner 17, 33: Seal member 20: Cylindrical surface 26: Piston 31: Holding plate 32
:bolt

Claims (1)

[Claims] A ceramic heat-insulating engine characterized in that a sealing member is fitted between a cylinder body and a lower end of a cylinder liner.