JPS6041207B2 - Internal combustion engine hot plug - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applied to a hole for an auxiliary combustion chamber provided in a cylinder head of an internal combustion engine, and forms a partition wall and a hole from the main combustion chamber. Concerning hot plugging of internal combustion engines.

[Conventional technology]

Compared to conventional hot plugs, hot plugs are made of steel, which has relatively low heat resistance, so the edge of the opening hole is easily overheated by the combustion flame and overturns.In addition to the hot plug itself having a large heat capacity, its thermal conductivity is low. Since the heat generated by combustion in the auxiliary combustion chamber is absorbed by the hot plug, the temperature of the combustion flame becomes low, and when the engine temperature is low, such as when starting, the combustion flame ejects from the exhaust hole. Ignition and combustion in the assisted main combustion chamber are delayed, reducing engine output and causing globe lag. However, there were drawbacks such as the fact that it took time for the secondary combustion chamber to ripen.

In order to overcome these drawbacks, attempts have been made to make hot plugs out of ceramic, which has good heat resistance and low heat capacity. It is easily damaged during the process of fixing the head to the board, and the hot plug is more difficult to maintain than the aluminum cast alloy and cast iron, which is the parent material of the cylinder head, so when the engine gets hot, the hot plug and cylinder There are problems such as a decrease in the bonding force with the head and the creation of gaps.

[Problem that the invention seeks to solve]

The present invention solves the above-mentioned drawbacks of ceramics, and provides a hot plug for internal combustion engines that makes it easy to iron the cylinder head and prevents the bonding force between the hot plug and the cylinder head from decreasing when the engine is at high temperature. This is what we provide.

[Means for solving problems]

In the present invention, zinc,
It is constructed by depositing a metal layer that is higher in quality than cylinder head materials such as metals such as aluminum, copper, and silver, or alloys thereof, and has a higher coefficient of thermal expansion.

〔Example〕

Next, the present invention will be explained based on embodiments shown in the drawings.

A is a hot plug according to the present invention, in which a metal layer 3 is formed around the outer periphery of a cylindrical container-shaped hot plug body 2 in which a hole 1 is provided.

The hot plug body 2 is made of ceramic aggregates such as alumina, oxides such as silicic acid, carbides such as silicon carbide and aluminum carbide, and nitrides such as silicon nitride and aluminum nitride, and the metal layer 3 is made of zinc to aluminum. The cylinder of the ceramic hot plug body 2 is made of a metal such as copper, silver, or an alloy thereof, which has a high coefficient of thermal expansion, and has a melting point not lower than 40,000, and is plasma sprayed or coated as a paste and fired. It is uniformly formed with a thickness of 40 microns to 500 microns on the outer periphery which is the joint surface with the head.As shown in Figure 2, the hot plug A of the present invention has an auxiliary combustion hole provided in the cylinder head. It is inserted into the lower side of h so that its lower end surface is flush with the lower surface of the cylinder head, forming an auxiliary combustion chamber S.

In the work of press-fitting this hot plug A into hole h,
The metal layer 3 alleviates the external force applied to the hot plug A, prevents damage to the ceramic hot plug body 2, and facilitates press-fitting. Furthermore, when the engine is operated and reaches high temperatures, the ceramic is replaced by cast iron, which is the base material of the cylinder head.
Since the coefficient of thermal expansion is lower than that of cast aluminum alloy, the bonding force between the hot plug A and the hole h of the cylinder head is weakened, but if the cylinder head is made of cast iron, the metal layer 3 may be made of cast iron such as aluminum, copper, or silver. By using a material with a large coefficient of thermal expansion, the difference in expansion between the hot plug A and the hole h of the cylinder head is compensated for and a decrease in bonding force is prevented. Note that it is desirable to insert a ring-shaped gasket G as shown in FIG. 2 in order to buffer the hot plug upper end surface and the hole of the cylinder head in the direction of the hole.

[Operations and Effects] As described above, since the hot plug of the present invention has a metal layer adhered to the ceramic hot plug body, iron adhesion to the cylinder head is easy, and the hot plug and cylinder head are easily bonded to each other when the engine is at high temperature. This increases the bonding force with the hot plug and prevents it from rattling.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the hot plug according to the present invention, and FIG. 2 shows the hot plug installed in an engine. In the figure, 2... hot plug body, 3... metal layer. Figure 1 Figure 2

Claims (1)

[Claims] 1. The entire outer peripheral surface of the cylindrical ceramic hot plug body, which is the mating surface with the cylinder head, is made of metals such as zinc, aluminum, copper, and silver, or their alloys, which are softer than cylinder head materials and have a higher coefficient of thermal expansion. A hot plug for an internal combustion engine that is made by depositing a large metal layer.