JPS6229621Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the structure of a sub-combustion chamber of an internal combustion engine.

Combustion methods for internal combustion engines, especially diesel engines, include direct fuel injection and sub-combustion (indirect fuel injection).Furthermore, sub-combustion includes vortex combustion, which has a high combustion efficiency. Because it has characteristics such as high height, it is often used in relatively small engines.

By the way, in this vortex combustion method, cracks are likely to occur at the acute corners of the nozzle member due to the high thermal load, and various measures have been taken to prevent the occurrence of cracks.

However, although all of the conventional techniques have achieved some degree of effectiveness, they are still insufficient, and a proposal for an auxiliary combustion chamber that can completely suppress the occurrence of cracks is desired.

The present invention was developed based on the above-mentioned circumstances, and its purpose is to provide a sub-combustion chamber in which cracks do not occur in the nozzle member.

According to the present invention, the nozzle member is made of super heat-resistant steel, the combustion chamber member is made of a good heat conductor, and these two members are engaged at the engaging portion and integrated. The inner surface of the combustion chamber is chrome-plated or hard alumite-treated to prevent oxidative corrosion caused by flames.

Embodiments of the present invention will be described below with reference to the accompanying drawings, but first an outline of the vortex combustion system will be explained with reference to FIG. FIG. 1 is a sectional view showing only the main parts. A cylinder head 2 is attached to a cylinder block 1, and a nozzle member 3 and a combustion chamber member 4 are attached to this cylinder head. As is well known, the cylinder block 1 has a piston 6 equipped with piston rings 5, 5 that reciprocates within a cylindrical liner 7, and the generated heat is cooled by cooling water 8. It's summery. The cylinder head 2 is attached to the cylinder block 1 with a seal member 9 in between. A sub-combustion chamber 11 is formed within the cylinder head 2.

A nozzle hole 14 is obliquely provided in the nozzle member 3, and combustion gas is sent into the main combustion chamber from this nozzle hole.
A good vortex flow is generated within the main combustion chamber, resulting in uniform combustion.

By the way, according to the prior art, the combustion chamber members constituting the auxiliary combustion chamber are made of carbon steel such as SCM420, and the nozzle member 3 is made of a heat-resistant alloy such as SUH3, which are the same steel materials. It was integrated by friction welding. When constructed from such a material, the heat generated in the nozzle member is transmitted to the cooling water 8 via the seal member 9, and is also transmitted to the cooling water 13 of the cylinder head 2, so that some degree of cooling is achieved. , there are problems with the heat resistance of the material of the nozzle member and a large thermal load on the nozzle member.
There was a problem in that cracks were formed at the corners A and B on the acute angle side of the nozzle hole 14.

The present invention has been proposed to deal with the occurrence of such cracks, and embodiments of the present invention will be described below with reference to FIGS. 2 to 4. The shape of the constituent members of the auxiliary combustion chamber in which the present invention is implemented is roughly the same as that of the conventional one, and the combustion chamber member 40 has an annular shape, and a lower combustion chamber 41 with a trapezoidal cross section is formed inside. The nozzle member 30 has a substantially disk shape, and a nozzle hole 31 is provided diagonally outward from a substantially central portion thereof. The two members 40, 30 are integrated at the engaging portion, that is, the stepped portion 32, for example, by cold fit.

According to the present invention, the combustion chamber member 40 having such a shape is made of a material with good thermal conductivity, such as aluminum or copper. If it is made of aluminum, the circumferential surface is hard alumite treated to prevent oxidation corrosion, and if it is made of copper, it is chrome plated. In this way, the inner peripheral surface of the good thermal conductor is subjected to corrosion prevention treatment 42, 42. According to the present invention, the nozzle member 30 is made of super heat-resistant steel (Inconel or Nimonik "registered trademark"). These two members 30, 40 are integrated by cold fitting, for example, and another embodiment of this integration is shown in FIG. 3, and the main parts are shown enlarged in FIG. ing. That is, the spout member 30
A columnar vertical portion 32 is provided between the upper surface a and the upper surface b.
a, a tapered portion 32b whose diameter is reduced toward the center,
The second vertical portion 32c has a diameter smaller than that of the vertical portion 32a.
An engaging portion 32 is formed. The combustion chamber member 40 also includes these portions 32a, 32.
An engaging portion having a shape compatible with the portions b and 32c is formed. Both members 30 and 40 are integrated by these engaging portions 32. In this example, a cold fit may also be used.

Since the auxiliary combustion chamber, that is, the combustion chamber member and the nozzle member according to the present invention are configured as described above, the heat of the nozzle member is transmitted to the cooling water 13 through the combustion chamber member made of a good heat conductor. Therefore, the thermal load on the nozzle member is reduced, and the occurrence of cracks, which conventionally tend to occur, is prevented. In addition, combustion chamber members are made of good thermal conductors, such as copper and aluminum, which have large coefficients of thermal expansion, so as the temperature of the auxiliary combustion chamber rises, they expand and become tightly attached to the cylinder head. Become. Therefore, as the temperature increases, the degree of adhesion increases, heat conduction improves, and the cooling effect is further enhanced. On the contrary, it contracts when the temperature is low, such as when starting the engine, and a gap is created between the cylinder head and the cylinder head, which acts as a heat insulator and prevents unnecessary overcooling. Therefore, it has the advantage of being effective for starting performance and warm-up performance. Furthermore, since the inner surface of the combustion chamber member is treated to prevent corrosion, it is highly durable.

Furthermore, when integrating the combustion chamber member and the nozzle member using such materials, it is difficult to integrate them by friction welding because the melting points of each material are different. By integrating by fitting or the like, the combustion chamber member made of a good heat conductor and the nozzle member made of super heat-resistant steel can be easily integrated, and the workability is also very good.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the main parts of an internal combustion engine equipped with a sub-combustion chamber, and FIGS. 2 to 4 are views showing embodiments of the present invention, and FIG. 2 shows the components of the sub-combustion chamber. 3 is a sectional view similar to FIG. 2 showing another embodiment, and FIG. 4 is a sectional view showing C in FIG. 3.
FIG. DESCRIPTION OF SYMBOLS 1... Cylinder block, 2... Cylinder head, 30... Nozzle member, 31... Nozzle hole, 40...
Combustion chamber member, 41...lower combustion chamber, 32...engaging portion.

Claims (1)

[Scope of utility model registration request] A combustion chamber member having an annular shape and having a lower combustion chamber therein, and a nozzle member having a nozzle hole extending diagonally through the cylinder from a substantially central position, both of which are inserted into the cylinder head. In the combustion chamber forming the auxiliary combustion chamber, the combustion chamber member is made of a good heat conductor, the nozzle member is made of super heat-resistant steel, the two members are integrated at an engaging part, and the heat conductor is made of a good heat conductor. A structure of an auxiliary combustion chamber of an internal combustion engine, characterized in that the inner surface of a combustion chamber member made of a good conductor is treated to prevent oxidation corrosion caused by flame.