JPH088280Y2 - Integrated cylinder block for internal combustion engine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated cylinder block of an internal combustion engine in which a cylinder part having a cylinder bore and a head part defining a combustion chamber are integrally cast.

2. Description of the Related Art A main body of an internal combustion engine for an automobile is generally divided into a cylinder block and a cylinder head along an upper end of a cylinder and cast, and the two are bolted together through a cylinder head gasket. Has become.

On the other hand, for example, Japanese Utility Model Publication No. 62-69045 and Japanese Utility Model Publication No. 62-69045
-69046, etc., discloses an integral cylinder block in which a cylinder portion and a head portion are integrally cast. In this integrated cylinder block, the risk of leakage of cooling water and combustion gas at the cylinder head gasket is completely eliminated, and the flow of cooling water around the combustion chamber is improved, improving cooling performance. There are advantages such as

Also, when this type of integrated cylinder block is formed of a light alloy such as an aluminum alloy, a cylinder liner made of, for example, cast iron is integrally cast on the inner circumference of the cylinder wall of the cylinder part, so-called dry liner type. I have something to do.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention By the way, in the conventional configuration in which the cylinder block and the cylinder head are divided along the upper end of the cylinder, the combustion pressure is received by the cylinder head, and this is transmitted via the cylinder head bolt and the boss portion on the cylinder block side. It is transmitted to the lower part of the cylinder block in a widely dispersed form. Therefore, a strong tensile force does not act on the cylinder wall.

On the other hand, in the integrated cylinder block in which the head part is integrated, the combustion pressure received by the head part is transmitted to the lower part of the cylinder part through the cylinder wall.
The cylinder wall receives the strongest tensile force.

Therefore, as shown in FIG. 3, the cylinder wall 21
When a separate cylinder liner 22 is cast on the inner circumference, stress concentration occurs on the edge 23 portion on the upper end outer circumference side of the cylinder liner 22, and cracks 24 as shown in the figure tend to occur on the cylinder wall 21 from there. In FIG. 3, 25 is a water jacket wall and 26 is a water jacket.

Further, in the divided conventional structure, since the cylinder head gasket with high heat insulation is provided along the upper end of the cylinder, heat transfer from the cylinder head to the cylinder block is suppressed, and the temperature of the upper part of the cylinder wall is reduced. Relatively low.

On the other hand, in the structure of the integral type cylinder block in which the cylinder wall is integrated with the head portion, the temperature of the upper portion of the cylinder wall becomes extremely high, and the cylinder bore diameter increases considerably due to thermal expansion. Therefore, problems such as deterioration of the combustion gas sealing property and increase of oil consumption are likely to occur.

Therefore, according to the present invention, a cylinder part having a cylinder bore and a head part defining a combustion chamber are integrally cast, and a separate cylinder is provided on the inner circumference of the cylinder wall of the cylinder part. In an integrated cylinder block of an internal combustion engine in which a liner is cast, a fiber reinforced layer that cylindrically surrounds the cylinder liner is provided on at least an upper portion of the cylinder wall, and an upper end portion of the fiber reinforced layer is provided at an upper end of the cylinder liner. It is characterized in that it extends further upward and extends toward the inner peripheral side so as to cover the outer peripheral side edge of the upper end of the cylinder liner.

Action Since the outer peripheral edge of the upper end of the cylinder liner is covered by the upper end of the fiber reinforced layer, cracks are prevented from occurring. Further, since the coefficient of thermal expansion of the fiber-reinforced layer is extremely small, the thermal expansion in the radial direction of the cylinder bore is suppressed.

Embodiment Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an integrated cylinder block 1 according to the present invention.
It is sectional drawing which shows the whole structure.

In this cylinder block 1, a cylinder part 2 in which a large number of cylinder bores are arranged in a row, and a head part 3 located above the cylinder part 2 and defining a combustion chamber are integrally cast from, for example, an aluminum alloy. The skirt portion 4 and the bulkhead 5 are integrally formed in the lower portion of the cylinder portion 2, and the intake port 6, the exhaust port 7, the cam bracket portion 8 are provided on the head portion 3 side. Etc. are formed. A main bearing portion 9 and a bearing cap 10 are fastened to the bulkhead 5 with a pair of cap bolts 11.

Further, in the cylinder portion 2, a water jacket wall 13 is formed so as to surround the outer side of the cylinder wall 12 having a cylindrical shape, and a water jacket 14 for cooling the cylinder portion is formed between them. . A water jacket 15 is formed in the head portion 3 as a core so as to surround the combustion chamber, the exhaust port 7, and the like. Water jacket on the head 3 side 15
Is communicated with the water jacket 14 on the cylinder portion 2 side in a wide range without being restricted by the cylinder head gasket.

A cylinder liner 16 made of, for example, cast iron is cast in the cylinder portion 2 of the cylinder block 1 for each cylinder. The cylinder liners 16 each have a cylindrical shape and are of a dry liner type supported on the inner circumference of the cylinder wall 12.

A fiber reinforced layer 17 made of so-called FRM (fiber reinforced metal composite material) is provided on the back surface of the cylinder liner 16 as a part of the cylinder wall 12. This fiber-reinforced layer 17 is obtained by preforming a long carbon fiber or a fiber such as silicon nitride or alumina into a predetermined cylindrical shape through a binder, and casting this into the cylinder block 1 at the time of casting.
The cylinder liner 16 is used in the illustrated example.
It is formed so as to surround the upper two-thirds of the area in a tubular shape. The fibers may be arranged regularly or irregularly. Further, since the thermal expansion in the radial direction of the cylinder wall 12 and the cylinder liner 16 becomes larger toward the upper portion, the fiber reinforced layer 17 is thicker toward the upper portion and the fibers are densely mixed. Then, the upper end 17a of the fiber reinforced layer 17,
As shown in detail in FIG. 2, the cylinder liner 16 extends slightly upward from the upper end and is bent inward, so that the outer peripheral edge 16a at the upper end of the cylinder liner 16 is covered. ing.

Therefore, according to the above configuration, even if a strong tensile force acts on the cylinder wall 12 by the combustion pressure, the peripheral portion of the edge 16a that causes stress concentration is effectively reinforced as the fiber reinforced layer 17, It does not cause cracks. In particular, since the outer peripheral edge 16a at the upper end of the cylinder liner 16 is covered by the fiber reinforced layer 17 so as to be wrapped therein, it is effective to form a crack that easily occurs along the upper end surface or the outer peripheral surface of the cylinder liner 16 starting from the edge 16a. Can be prevented. Further, in the illustrated example, since the fiber reinforced layer 17 extends considerably downward, the strength of the cylinder wall 12 as a whole against the tensile force is remarkably improved.

Further, the coefficient of thermal expansion of the fiber-reinforced layer 17 containing fibers such as carbon is much smaller than that of a simple substance of metal, so that the cylinder wall 12 and the cylinder liner 16 expand in the radial direction due to the temperature increase at the upper end of the cylinder bore. Is suppressed. In particular, in the above-described embodiment, since the radial expansion is strongly suppressed toward the upper part, the result is offset by the temperature gradient of the cylinder bore, and it is possible to keep the bore diameter of the cylinder bore substantially uniform over the entire length during actual operation. it can.

Effect of the Invention As is clear from the above description, in the integrated cylinder block of the internal combustion engine according to the present invention, by integrating with the head portion, the tensile stress is easily concentrated on the outer peripheral portion of the upper end of the cylinder liner. Can be reinforced.
In particular, since the outer peripheral edge at the upper end of the cylinder liner is covered with the fiber reinforced layer so as to be wrapped therein, it is possible to reliably prevent the occurrence of cracks that tend to occur starting from the edge. Further, by being integrated with the head portion, it is possible to suppress thermal expansion in the upper portion of the cylinder bore, which becomes extremely high temperature, and prevent deterioration of sealing property against combustion gas and increase of oil consumption.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an integrated cylinder block according to the present invention, FIG. 2 is an enlarged sectional view of an essential part thereof, and FIG. 3 is a sectional view of a conventional integrated cylinder block essential part. . 1 ... Cylinder block, 2 ... Cylinder part, 3 ... Head part, 12 ... Cylinder wall, 16 ... Cylinder liner, 17 ... Fiber reinforced layer.

Claims (1)

[Scope of utility model registration request] 1. A cylinder part having a cylinder bore and a head part defining a combustion chamber are integrally cast, and
In an integrated cylinder block of an internal combustion engine in which a separate cylinder liner is cast on the inner circumference of the cylinder wall of the cylinder portion, a fiber reinforced layer that cylindrically surrounds the cylinder liner is provided at least on the upper part of the cylinder wall. An integrated cylinder block for an internal combustion engine, wherein an upper end portion of the fiber reinforced layer is extended upward from an upper end of the cylinder liner and is extended to an inner peripheral side so as to cover an outer peripheral edge of the upper end of the cylinder liner. .