JPH0734875A - Cylinder head for engine having subsidiary chamber - Google Patents

Abstract

PURPOSE:To fit a main part to a sub-combustion part with certainty by forming the main part of aluminum for lightening and adopting material having small thermal expansion coefficient to the subsidiary chamber. CONSTITUTION:In a cylinder head 2 of an engine 1 having a sub-combustion chamber, a main part 3 is integrated with a sub-combustion chamber part 4. The sub-combustion chamber part 4 is divided into an upper side part 4a and a lower side part 4b, which can be fitted to each other. The main part 3 is cast in aluminum. In casting the main part 3, the subsidiary chamber part 4 which is previously formed by heat resistant material having thermal expansion coefficient smaller than that of the aluminum material is integrally cast.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder head for an engine with a secondary combustion chamber.

[0002]

2. Description of the Related Art In the prior art, there is a cylinder head of an engine with an auxiliary combustion chamber, which is constructed as follows, for example, as shown in FIG. That is, the main portion 3 of the cylinder head 2 and the auxiliary combustion chamber portion 4 of the engine 1 with the auxiliary combustion chamber
And the auxiliary combustion chamber part 4 are divided into an upper part 4a and a lower part 4b so that they can be fitted to each other. Usually, the main portion 3 of the cylinder head 2
Is formed by forming the air supply port 5, the exhaust port 6, the water jacket 7 and the upper portion 4a of the auxiliary combustion chamber portion 4, and is cast, and particularly the lower portion 4b of the auxiliary combustion chamber portion 4 exposed to high temperature combustion gas. Are separately formed of a heat-resistant material, and are integrally formed by being machined after the main portion 3 is cast.

[0003]

The above-mentioned conventional techniques have the following problems. The use of an aluminum material for the main part 3 of the cylinder head 2 has the advantage of good heat conduction and light weight, but the lower part 4b of the auxiliary combustion chamber part 4 is formed of a highly heat-resistant iron material or the like. After the main portion 3 has been cast, it is fitted by machining. Therefore, the aluminum material having a large coefficient of thermal expansion at high temperature during engine operation expands, and the fitting with the lower portion 4b of the sub-combustion chamber portion 4 having a small coefficient of thermal expansion becomes loose. The side part 4b may come off. It is an object of the present invention to secure fitting between a main part and a sub combustion chamber part by using a heat resistant material having a small thermal expansion coefficient in the sub combustion chamber part while reducing the weight of the main part with an aluminum material. .

[0004]

In order to achieve the above object, the present invention adds the following improved structure to the above prior art as shown in FIGS. 1 and 2, for example. First invention (see FIG. 1) Main part 3 of cylinder head 2 of engine 1 with auxiliary combustion chamber
Is cast from an aluminum material, and when the main portion 3 is cast, the auxiliary combustion chamber portion 4 previously formed from a heat-resistant material having a smaller thermal expansion coefficient than the aluminum material is cast into an integral structure. Second invention (see FIG. 1) When casting the main portion 3 of the cylinder head 2 of the engine 1 with the auxiliary combustion chamber of the first invention, after casting the upper portion 4a of the auxiliary combustion chamber portion 4, The lower part 4b is fitted to the upper part 4a to be integrally formed. Third invention (see FIG. 2) After fitting the upper portion 4a and the lower portion 4b of the auxiliary combustion chamber portion 4 of the cylinder head 2 of the engine 1 with the auxiliary combustion chamber of the first invention, the main When the part 3 is cast, the auxiliary combustion chamber part 4 is cast to form an integral part.

[0005]

The present invention operates as follows. First invention (see FIG. 1) The sub-combustion chamber portion 4 is formed in advance with a heat-resistant material having a smaller thermal expansion coefficient than the aluminum material used for the main portion 3 of the cylinder head 2. Further, it is more preferable to form a protruding portion 4c for preventing coming off on the outer periphery of the sub-combustion chamber portion 4. The sub-combustion chamber portion 4 is integrally formed by casting when the main portion 3 is cast. Main part 3 above
At the high temperature during casting, the aluminum material having a larger coefficient of thermal expansion expands more than the heat-resistant material of the sub-combustion chamber portion 4 and contracts when the molten aluminum cools and solidifies. Tighten the chamber part 4 firmly. Further, during operation of the engine, the sub-combustion chamber portion 4 is more than the main portion 3 cooled by the water jacket 7 or the like.
Since it becomes hotter and expands, it is firmly held, and the convex portion 4c on the outer periphery of the auxiliary combustion chamber portion 4 bites into the main portion 3 and can be held more reliably. Second invention (see FIG. 1) In the cylinder head of the engine with the auxiliary combustion chamber of the first invention, after casting the upper portion 4a of the auxiliary combustion chamber portion 4 when casting the main portion 3, The upper portion 4a and the lower portion 4b are fitted to each other to be integrally formed. By doing so, the machining of the auxiliary combustion chamber portion 4 can be facilitated. Third invention (see FIG. 2) In the cylinder head of the engine with the auxiliary combustion chamber of the first invention, after the upper portion 4a and the lower portion 4b of the auxiliary combustion chamber portion 4 are fitted, When the part 3 is cast, the auxiliary combustion chamber part 4 is cast into one body. By doing so, it is possible to facilitate the machining of the auxiliary combustion chamber portion 4 as in the second aspect of the invention.

[0006]

The present invention has the following effects because it is constructed and operates as described above. The sub-combustion chamber part 4 is previously formed and formed on the main part 3 of the cylinder head 2 with a heat-resistant material having a thermal expansion coefficient smaller than that of the aluminum material used, and the sub-combustion chamber part 4 is cast when the main part 3 is cast. It is configured as one. Therefore, the aluminum melt that has expanded at a high temperature during the casting of the main portion 3 contracts when it cools and solidifies, and firmly tightens the auxiliary combustion chamber portion 4. Further, during operation of the engine, the auxiliary combustion chamber portion 4 has a higher temperature than the main portion 3 and expands, so that the auxiliary combustion chamber portion 4 is held more firmly. This makes it possible to ensure the fitting between the main portion and the auxiliary combustion chamber portion by using the heat-resistant material having a small thermal expansion coefficient for the auxiliary combustion chamber portion while reducing the weight of the main portion with the aluminum material.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. First embodiment of the invention (see FIG. 1) FIG. 1 is a cross-sectional view of a main part of a cylinder head of an engine with a secondary combustion chamber. In the figure, an engine 1 with a secondary combustion chamber has an engine body formed by sequentially mounting and fixing a cylinder head 2 and a head cover (not shown) on an upper surface of a cylinder block 10. A piston 12 is slidably fitted into a cylinder 11 in the cylinder block 10, and the piston 12 is interlockingly connected to a crankshaft (not shown) via a piston pin 13 and a connecting rod 14. Further, the main portion 3 of the cylinder head 2 and the auxiliary combustion chamber portion 4 are integrally formed, and the auxiliary combustion chamber portion 4 is divided into an upper portion 4a and a lower portion 4b so that they can be fitted to each other. I am doing it. The main portion 3 is formed by casting the air supply port 5, the exhaust port 6, the water jacket 7, etc. with an aluminum material. Furthermore, in advance,
The auxiliary combustion chamber portion 4 is formed by placing a heat resistant material having a smaller thermal expansion coefficient than the aluminum material (for example, iron material or ceramic material), and the auxiliary combustion chamber portion 4 is placed on the main portion 3 described above.
It is integrally formed by casting at the time of casting. Further, it is more preferable to form a protruding portion 4c for preventing coming off on the outer periphery of the sub-combustion chamber portion 4. Reference numeral 15 is an intake / exhaust valve, and reference numeral 16 is a fuel injection valve in the case of a diesel engine.

Second embodiment of the invention (see FIG. 1) When casting the main part 3 of the cylinder head 2 of the engine 1 with the auxiliary combustion chamber of the first invention, the upper part 4a of the auxiliary combustion chamber part 4 is cast. After that, the lower portion 4b is fitted to the upper portion 4a to be integrally formed. Third embodiment of the invention (see FIG. 2) FIG. 2 is a view corresponding to FIG. After fitting the upper portion 4a and the lower portion 4b of the sub-combustion chamber portion 4 of the cylinder head 2 of the engine 1 with the sub-combustion chamber of the first aspect of the invention, the sub-combustion chamber during casting of the main portion 3 The part 4 is cast and formed integrally. In this case, it is preferable to form a protrusion 4d for preventing slip-out also on the outer periphery of the lower portion 4b.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part of a cylinder head of an engine with a secondary combustion chamber, showing a first invention and a second invention embodiment.

FIG. 2 is a diagram corresponding to FIG. 1 and showing a third embodiment of the invention.

FIG. 3 is a diagram corresponding to FIG. 1 showing a conventional example.

[Explanation of symbols]

1 ... Engine with auxiliary combustion chamber, 2 ... Cylinder head, 3 ... Main part, 4 ... Secondary combustion chamber part, 4a ... Upper part, 4b ... Lower part.

Claims (3)

[Claims] 1. A main part (3) and a sub-combustion chamber part (4) of a cylinder head (2) of an engine (1) with a sub-combustion chamber are integrally formed, and the sub-combustion chamber part (4) is formed. Upper part (4
In a cylinder head of an engine with a secondary combustion chamber, which is formed by being divided into a) and a lower part (4b) and which can be fitted to each other, the main part (3) is formed by casting with an aluminum material,
When the main part (3) is cast, the sub-combustion chamber part (4), which is previously formed of a heat-resistant material having a smaller thermal expansion coefficient than the aluminum material, is cast and integrally formed. Engine cylinder head. 2. After casting the upper part (4a) of the auxiliary combustion chamber part (4) at the time of casting the main part (3), the lower part (4b) is attached to the upper part (4a). The cylinder head for an engine with a sub-combustion chamber according to claim 1, wherein the cylinder head is fitted and configured integrally. 3. The upper part (4a) of the sub-combustion chamber part (4).
After fitting the lower part (4b) with the main part,
2. The cylinder head for an engine with a sub combustion chamber according to claim 1, wherein the sub combustion chamber portion (4) is cast into one body during the casting of (3).