JPS5819321Y2 - Diesel engine pre-combustion chamber cooling system - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a device for cooling the front end side of a pre-combustion chamber of an easel engine.

In a pre-combustion chamber type easel engine, the pre-combustion chamber is provided through the cylinder head.

However, the tip side of the pre-combustion chamber is exposed to the main combustion chamber and is constantly exposed to high-temperature jet flames, making it subject to severe temperature conditions. Most of these troubles, which are often caused by overheating, are caused by uneven temperature distribution near the front end of the pre-combustion chamber and the attachment to the cylinder head.

In order to prevent overheating on the tip side of the pre-combustion chamber, various methods have been proposed, such as a device that directs the cooling water flow mainly toward the tip side, but each known method has a complicated structure and may be expensive. It also had various drawbacks, such as placing restrictions on the structure of the cylinder head and furthermore, the cooling effect on the tip side was insufficient.

The present invention aims to improve the above-mentioned drawbacks and provide a device that effectively cools the front end side of the pre-combustion chamber with a simple structure.

This will be explained below using figures.

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line AA in FIG.

Referring to the figure, a cylinder head 1 is provided with a cooling water chamber 2, and a pre-combustion chamber 3 is provided through the cooling water chamber 2.

In this embodiment, the pre-combustion chamber 3 is an upper body 3a.
and a lower body 3b, but it goes without saying that an integral structure may also be used.

A skirt portion 4 that hangs down in an annular shape is integrally provided on the lower body 3b, and the hanging end of the skirt portion 4 is in contact with the lower surface 5 of the cooling water chamber 2 or faces the lower surface 5 of the cooling water chamber 2 with a slight gap therebetween.

The skirt portion 4 forms an annular cooling water passage 6 around the lower body 3b, and the skirt portion 4 includes two open lowers to form a cooling water inlet and an outlet to the cooling water passage 6. 8 is provided.

The open lowers 8 are provided at positions substantially symmetrical to each other, and one of the open lowers is provided at a position facing the cooling water inlet 9 into the cooling water chamber 2 .

An end portion of the lower body 3b passes through the lower surface 5 and faces the main combustion chamber 10.

The present invention is constructed as described above and operates as follows.

Cooling water is introduced from a cooling water inlet 9 on the cylinder block side into the cooling water passage 6 via the open lower part.

The introduced cooling water branches left and right, flows along the periphery of the lower body 3b, and flows out into the cooling water chamber 2 through the opening 8.

The cooling water flowing through the cooling water passage 6 not only cools the lower body 3b but also cools the lower surface 5 of the cooling water chamber 2 near the mounting part, thereby making the temperature distribution uniform on the lower body 3b and the lower surface 5 near the mounting part. Peel off.

Since the present invention is as described above, the lower body 3b
The temperature distribution near the tip of the lower body 3b and the area where the lower body 3b is attached to the cylinder head 1 is uniform, and there are no problems such as distortion due to differences in thermal expansion.

In addition, overheating of the tip side of the lower body 3b is prevented,
Improves durability.

Further, since the open lower lower part 8 is placed in a substantially symmetrical position and the cooling water flow is branched to the left and right, the flow lengths of the left and right branched water flows are the same, and the uniformity of temperature distribution is good.

Furthermore, when manufacturing the pre-combustion chamber, it is much easier to integrally form the cooling structure consisting of a skirt at the tip of the pre-combustion chamber than to provide it on the cylinder block.

Further, since the annular passage is formed by the skirt, the cooling water can flow in and out through the slit, and the formation of the slit is also simple.

Furthermore, since the cooling efficiency is related to the flow rate of cooling water, the flow rate on the surface of the pre-combustion chamber must be made as large as possible.

For this purpose, the flow path must have no restriction and the cross section of the flow path must be approximately the same, but if the skirt structure is used, the cross section of the flow path on the entire circumferential surface can be easily made the same, resulting in high cooling efficiency.

Further, since the skirt itself functions as a cooling fin, a further improvement in the cooling effect can be obtained by this amount alone.

In particular, since the skirt is integrally molded into the pre-combustion chamber,
The cooling efficiency of the fins is high.

Further, as described above, the pre-combustion chamber is not limited to the upper and lower two-piece structure.

Furthermore, the present invention can also be applied to a cooling device for the tip of a fuel injection nozzle, and in this case, it can be easily applied by providing a fuel injection nozzle in place of the pre-combustion chamber.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing one embodiment of the present invention, and Fig. 2 is a cross-sectional view showing an embodiment of the present invention.
It is an AA sectional view of the figure. 1 Niji cylinder head, 2: Cooling water chamber, 3: Pre-combustion chamber, 4
Varnishing force part, 5: Bottom surface, 6: Cooling water passage, 7, 8: Opening, 9: Cooling water inlet.

Claims (1)

[Scope of utility model registration request] In an easel engine, a pre-combustion chamber is provided by passing through a cooling water chamber provided in the cylinder head, and the tip side of the pre-combustion chamber passes through the lower surface of the cooling water chamber and faces the main combustion chamber. A skirt portion is integrally provided on the front end side of the combustion chamber, and a hanging end of the skirt portion substantially contacts the lower surface of the cooling water chamber to form an annular cooling water passage around the front end side of the pre-combustion chamber. Pre-combustion for a diesel engine, characterized in that at least two openings are provided at substantially symmetrical positions in the section, and at least one of the openings is provided opposite to a cooling water flow opening to the cooling water chamber. Room cooling system.