JPS5939158Y2 - Combustion chamber of two-stroke engine - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement in the combustion chamber of a two-stroke engine, which is composed of a cylinder head and a piston.

Two-stroke engines are made by casting the cylinder head and piston from aluminum alloy.

Then, a spark plug is placed in the center of the cylinder head, and combustion gas is compressed into the space created by the cylinder head and piston head, and is ignited by the spark plug, causing explosive combustion.

In 2-cycle engines, especially at low speeds, the exchange of old and new gas may become insufficient, resulting in abnormal combustion, and many pinholes may occur on the outer periphery of the combustion chamber of the cylinder head and on the outer periphery of the piston head. This may occur, reducing the durability of the cylinder head and piston.

Conventionally, this has been avoided by changing the cylinder head shape, compression ratio, ignition timing, etc. to prevent pinholes from occurring, but these have the disadvantage of lowering engine output and performance. .

This invention has been improved in view of these points, and the embodiments of the invention shown in the drawings will be described below.

Tighten the cylinder head 2 to the upper end of the cylinder 1.

A piston 3 is slidably inserted into the cylinder 1 and reciprocates.

Therefore, in the present invention, the cylinder head 2 and the piston 3 are cast from an aluminum alloy, and the outer circumference of the combustion chamber 4 of the cylinder head 2 and the outer circumference of the head 5 of the piston 3 are made of molten aluminum alloy. An annular body 6 made of a copper-based alloy or the like having a high point and good thermal conductivity is integrally formed by casting at the time of casting.

7 is a screw hole for attaching a spark plug.

The effect will be explained.

When abnormal combustion occurs, combustion starts from the part where the central spark plug is attached, and the combustion is transmitted outward, causing damage to the outer periphery of the combustion chamber 4 of the cylinder head 2 and the outer periphery of the head 5 of the piston 3. is the most affected.

In this part, a ring 6 with a high melting point and good thermal conductivity is added.
Since it is cast, abnormal combustion heat is quickly released to the outside, and its melting point is high, so it can prevent pinholes from forming when touched.

As explained above, this idea is that when the cylinder head and piston are cast from aluminum alloy, the outer periphery of the combustion chamber of the cylinder head and the outer periphery of the piston head have a higher melting point than cast aluminum alloy. Since the ring body is made of copper-based alloy, etc., which has good conductivity, it is possible to quickly dissipate heat to the outside even if abnormal combustion occurs, and there is no need to touch the material, which prevents the formation of many pinholes. Without,
Improves durability.

In this way, there is no need to adjust ignition timing, compression ratio, etc., and engine performance can be maintained at high levels.

[Brief explanation of drawings]

The figures show one embodiment of the present invention, with Figure 1 being a longitudinal sectional view and Figure 2 being a longitudinal sectional view.
The figure is a bottom view of the cylinder head, and FIG. 3 is a plan view of the piston. 2... Cylinder head, 3... Piston, 4...
Combustion chamber, 5...head, 6...ring body.

Claims (1)

[Scope of utility model registration request] When the cylinder head and piston are cast from aluminum alloy, the outer periphery of the combustion chamber of the cylinder head and the outer periphery of the piston head are made of cast aluminum alloy, a copper alloy with a high melting point and good heat conduction, etc. A two-stroke engine combustion chamber characterized by being cast.