JP2532142Y2 - Reciprocating internal combustion engine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston structure of a reciprocating internal combustion engine capable of efficiently receiving an instantaneous explosion pressure in a cylinder caused by ignition of a spark plug provided in a cylinder head.

[0002]

2. Description of the Related Art A piston structure of a conventional reciprocating internal combustion engine is as shown in FIG. That is, the upper end surface 31A of the piston 3A facing the ignition plug 2 provided in the cylinder head 1 is formed as a flat surface.

[0003]

However, if the upper end surface 31A of the piston 3A is formed as a flat surface as described above, the instantaneous explosion pressure at the time of the ignition explosion by the spark plug 2 is higher than the piston 3A having the flat surface. There is a problem that the instantaneous explosion pressure cannot be efficiently received, because the explosion pressure cannot be efficiently and simultaneously transmitted to the entire end face 31A.

[0004] For this reason, the size of the piston 3A cannot be reduced, which has been an obstacle to downsizing the structure of the entire engine. The present invention has been made in view of the above-described conventional circumstances, and is capable of efficiently receiving the instantaneous explosion pressure in the cylinder caused by the ignition of the ignition plug provided in the cylinder head, thereby obtaining a large output. It is another object of the present invention to provide a piston structure of a reciprocating internal combustion engine that can reduce the size of a piston at the same output as that of a conventional engine, and thereby reduce the size of the entire engine.

In order to achieve the above object, the present invention provides a piston head, which is provided on a cylinder head and has an upper end surface which is formed into a concave spherical surface, and which is opposed to an upper end surface of the piston of the cylinder head. The surface to be formed was formed on a concave surface having a deep center.

[0006]

As described above, since the upper end surface of the piston is formed into a concave spherical surface, the instantaneous explosion pressure caused by the ignition of the ignition plug provided on the cylinder head is simultaneously applied to the entire upper end surface of the piston having the concave spherical surface. In addition to receiving the explosion pressure evenly and receiving the explosion pressure over a large area, the instantaneous explosion pressure can be efficiently received.

As a result, while the output of the engine can be increased, the shape of the piston can be reduced, and the size of the engine can be reduced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a piston structure of a reciprocating internal combustion engine according to the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view showing one embodiment of a piston structure of a reciprocating internal combustion engine according to the present invention.

As shown in FIG. 1, the piston structure of the reciprocating type internal combustion engine according to the present invention has an upper end surface 3 of a piston 3 opposed to a spark plug 2 provided on a cylinder head 1.
1 is formed as a concave spherical surface. Note that reference numeral 4 in FIG.
Denotes a cylinder, reference numeral 5 denotes a connecting rod, reference numeral 6 denotes a crankshaft, reference numeral 7 denotes an intake valve, reference numeral 8 denotes an exhaust valve, and reference numeral 9 denotes a water jacket. As apparent from FIG. 1, the surface of the cylinder head 1 facing the upper end surface 31 of the piston 3 is formed in a concave surface having a deep center.

Next, the operation of the piston structure and the cylinder head of the reciprocating internal combustion engine having the above configuration will be described.
Now, when gasoline is sucked into the upper part of the piston 3, air is sucked in, and the compression process is completed in the cylinder 4, when the spark plug 2 is ignited, an explosion occurs instantaneously in the cylinder 4. The piston 3 is pushed down by this explosion pressure and descends, and the crankshaft starts rotating.

At this time, the instantaneous explosion pressure caused by the ignition of the ignition plug 2 is simultaneously and uniformly transmitted to the entire upper end surface 31 of the piston 3 having a concave spherical surface. Therefore, the explosion pressure transmitted to the peripheral end of the upper end surface 31 of the piston 3 having a concave spherical surface is equal to the upper end surface 31 of the conventional piston 3A having a flat surface.
A is larger than the explosion pressure transmitted to A, so that the vector acting in the vertical direction of the piston is also large.

The upper end surface 31 of the piston 3 having a concave spherical surface receives an explosive pressure over a large area. As described above, the instantaneous explosion pressure can be efficiently received by the upper end surface 31 of the piston 3 having the concave spherical surface, and the output of the engine can be increased. On the other hand, the shape of the piston can be reduced, and accordingly, the connecting rod 5 and the crankshaft 6 can be reduced in size, and the size of the entire engine can be reduced.

As is apparent from FIG. 1, in this reciprocating internal combustion engine, the upper end surface 31 of the piston 3 facing the ignition plug 2 provided on the cylinder head 1 is formed into a concave spherical surface. Since the surface of the piston 3 facing the upper end surface 31 is formed as a concave surface with a deeper center, the upper end surface 31 of the piston 3 and the surface of the cylinder head 1 facing the upper end surface of the piston 3 are different from each other. , The concave spherical surface and the concave surface face each other. Therefore, the instantaneous explosion pressure caused by the ignition of the spark plug 2 can be more efficiently received not in the side direction of the cylinder 4 but in the direction of the upper end surface 31 of the piston 3 by the cooperation of the concave spherical surface and the concave surface. it can. This can save fuel.

[0014]

As described above, according to the present invention, it is possible to efficiently receive the instantaneous explosion pressure in the cylinder due to the ignition of the ignition plug provided in the cylinder head and obtain a large output. In addition, the shape of the piston at the same output can be made smaller than that of the conventional one, so that the whole engine can be downsized.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a piston structure of a reciprocating internal combustion engine according to the present invention.

FIG. 2 is a longitudinal sectional view showing a piston structure of a conventional reciprocating internal combustion engine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Spark plug 3 Piston 31 Upper end surface (concave spherical surface)

Claims (1)

(57) [Scope of request for utility model registration] 1. A concave surface in which an upper end surface of a piston facing an ignition plug provided in a cylinder head is formed into a concave spherical surface, and a surface of the cylinder head facing the upper end surface of the piston has a deeper center. A reciprocating internal combustion engine characterized by being formed as follows.