JPS6359009B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to ceramic cylinder heads of multi-cylinder internal combustion engines. [Prior Art] Conventionally, there has been a demand for internal combustion engines to be made of ceramic in order to make them lighter and more efficient.
In addition, a number of internal combustion engines have been proposed that use ceramic parts in some parts, such as the valve seat of the cylinder head, the hot plug, and the outer periphery of the rotary valve. (For example, Japanese Unexamined Patent Publication No. 55-57646, Japanese Utility Model Application No. 56-45105, etc.) [Problems to be solved by the invention] However, in the past, ceramic parts were fitted into a small part of the engine. However, the effects of reducing weight and increasing efficiency are extremely limited, and there are also problems such as a decrease in sealing performance due to the difference in thermal expansion and wear of the metal due to sliding between the ceramic surface and the metal surface.
It had the disadvantage of low practicality and durability. Furthermore, as is well known, ceramic materials have higher hardness and heat resistance than metal materials, and are lighter in weight, but they have poor processing and formability, and low toughness and thermal shock resistance. Therefore, in order to use ceramics for internal combustion engines, it is necessary to develop an internal combustion engine structure that is suitable for ceramic materials. An object of the present invention is to provide a cylinder head structure most suitable for use in ceramic for multi-cylinder internal combustion engines. In particular, the structure is simple, it is difficult to apply impact force, and it is easy to mount on vehicles etc. Furthermore, it prevents incomplete sealing due to the difference in thermal expansion between the rotary valve body and the cylinder head body, and the sliding surface To provide a ceramic cylinder head that can be used without any lubrication. [Means for solving the problem] In order to achieve the above objective, a ceramic cylinder head body with intake holes and exhaust holes formed in the side wall is provided with one hole that intersects all of these intake holes, exhaust holes and the combustion chamber. A straight hole with a circular cross section is provided, and a curved hole for intake that communicates between the combustion chamber and the intake hole within a predetermined crank rotation angle range, and a curved intake hole that connects the combustion chamber with the exhaust hole within another predetermined rotation angle range. It has a curved exhaust hole that communicates with the chamber, and a cylindrical ceramic valve body that is linked to the engine's crankshaft is rotatably fitted into the valve body. [Operation and Effects of the Invention] The ceramic cylinder head of the present invention has a circular straight hole in the ceramic cylinder head body,
By rotatably fitting a cylindrical ceramic valve body into this straight hole to form a rotary valve, the following effects are produced. (a) Since both the valve body and the cylinder head body are made of ceramic, it is possible to prevent the sealing performance of the sliding surfaces from deteriorating due to differences in thermal expansion. (b) Since both sliding surfaces are ceramic surfaces, wear on one side can be prevented. In other words, if one of the straight hole in the cylinder head with the intake and exhaust holes and the valve body fitted into this straight hole are made of metal and the other is made of ceramic, the friction between the metal materials will be large and the durability will be significantly reduced. In contrast, in the present invention, both are made of ceramic material, which has excellent wear resistance and can eliminate this problem.There is no leakage at intake pressure or explosion pressure, and stable combustion of the engine can be achieved. , it has special effects such as being able to obtain . (c) The rotating surface can be formed smoothly, making it possible to eliminate lubrication. For ceramic cylinder heads, water cooling (cooling with a water jacket) is difficult to adopt due to the complex structure, so eliminating the need for lubrication is an important requirement for practical use. (d) Since the valve body only performs smooth rotational motion, impact force is less likely to be applied compared to a valve mechanism that performs reciprocating motion. In addition, both the cylinder head and valve body have a simple structure and a shape that prevents stress concentration, making it easy to manufacture when burning ceramic materials and reducing stress when thermal shock is applied. Concentration can be prevented. Furthermore, since the intake and exhaust holes in the valve body are curved, the intake manifold pipe and exhaust manifold pipe can be placed on the side of the multi-cylinder internal combustion engine, reducing the vertical dimensions of the engine, making it easier to mount on vehicles, small ships, etc. Excellent in [Example] Next, the present invention will be explained based on an example shown in FIG. Figure 1 shows a 4-stroke, 4-cylinder engine, S1
~S4 is each cylinder, CL is the crankshaft, P1
-P4 indicates a piston, and C1 to C4 indicate connecting rods. 1 is a cylinder head of an engine formed of a ceramic sintered body mainly made of ceramic having excellent thermal shock resistance such as silicon nitride, and 21, 23, 25, and 27 are one side wall of the cylinder head 1 that is substantially perpendicular to the cylinder axis. Exhaust holes for each cylinder provided in 22, 2
Reference numerals 4, 26, and 28 indicate intake holes of each cylinder in which the cylinder head 1 is provided, parallel to each intake hole, and 2 indicates an intake hole parallel to the crankshaft in the cylinder head such that these intake holes and exhaust holes intersect and communicate with each other. The circular cross-section straight hole 3 formed by the straight hole 2 is designed to fit tightly with the wall of the direct connection 2 and to allow smooth rotation.
The valve body is made of a sintered ceramic body mainly made of cylindrical silicon nitride fitted inside. The valve body 3 has curved exhaust holes 31, 33, 35, and 37 which are curved in an angle range of approximately 90 degrees and communicate between each exhaust port inlet and each fuel chamber within a predetermined rotation angle range, respectively. almost 90 to
Intake curved holes 32, 34, 36, and 38 are formed, which are curved in an angular range of 100 degrees, and communicate each intake hole inlet with each combustion chamber in a predetermined rotation angle range, respectively.
One end has a timing gear 4 fixed thereto, and is connected via a timing belt 41 to a drive gear 42 fixed to the end of the crankshaft CL. By providing the intake curved hole and the exhaust curved hole in the valve body 3 in this way, the valve body becomes one, which simplifies the structure and allows the valve body to be made thicker and the cross-sectional area of these curved holes to be larger. In this engine, ignition is performed in the order of S1 → S3 → S4 → S2, and the crank angle and intake, compression, explosion, and exhaust processes are performed as shown in Table 1.

[Table] FIG. 2 shows another embodiment. The engine of this embodiment has intake holes 21, 23, 25,
27 and exhaust holes 22, 24, 26, and 28 are respectively provided on the opposite side wall of the cylinder head.
Intake and exhaust curved holes 51, 52, 53, and 54 are provided which are curved in an angle range of approximately 90 degrees and communicate with the intake or exhaust holes at a predetermined rotation angle.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing one embodiment of an internal combustion engine with a ceramic cylinder head of the present invention, and FIG. 2 is a schematic perspective view showing another embodiment of the ceramic cylinder head of the present invention. In the figure, 1... cylinder head, 2... straight hole,
3, 5...Rotary valve disc, 21, 23, 2
5, 27...Exhaust hole, 22, 24, 26, 28...
... Intake hole, 31, 33, 35, 37... Curved hole for exhaust, 32, 34, 36, 38... Curved hole for intake, 51, 52, 53, 54... Curved hole for intake and exhaust.

Claims (1)

[Scope of Claims] 1. A cylinder head body made of ceramic with intake holes and exhaust holes formed in the side wall, these intake holes,
A straight hole having a circular cross section that intersects all of the exhaust hole and the combustion chamber is provided, and a curved hole for intake that communicates the combustion chamber and the intake hole within a predetermined crank rotation angle range is provided in the straight hole, A multi-layer valve having a curved exhaust hole that communicates the exhaust hole and the combustion chamber in another predetermined rotation angle range, and in which a cylindrical ceramic valve body is rotatably fitted and is linked to the crankshaft of the engine. Ceramic cylinder head for internal combustion engines. 2 The curved intake hole provided in the cylindrical valve body is
It is an intake/exhaust curved hole that also serves as an exhaust hole, and the intake/exhaust curved hole connects the intake hole and the combustion chamber within a predetermined rotation angle range, and communicates with the combustion chamber within another predetermined rotation angle range. The ceramic cylinder head according to claim 1, wherein the exhaust hole and the combustion chamber are communicated with each other.