JPS6172826A - Sub-chamber structure in engine - Google Patents

Abstract

PURPOSE:To absorb thermal deformation without damaging sealing performance, by constituting a sub-chamber forming member by a chamber member and a slidable sleeve provided outside the chamber member with an insulating air layer defined therebetween, and providing a seal means between the chamber member and the sleeve. CONSTITUTION:A sub-chamber forming member 2 is inserted into a bore 1a of a cylinder head 1 to form a sub-chamber 5 communicated through a discharge hole 4 to a main combustion chamber 3. The sub-chamber forming member 2 is constituted of a metal chamber member 6 and a metal sleeve 7 provided outside the chamber member 6. The chamber member 6 is in a hollow structure where the sub-chamber 5 is formed therein, and consists of an upper portion 6b, an intermediate portion 6d and a lower flange 6e. The sleeve 7 is cylindrical, and consists of an upper flange 7a and a cylindrical portion 7b. A lower end of the cylindrical portion 7b is in contact with an elastic seal member 12 provided at a shoulder portion 6g formed at a lower end of the intermediate portion 6d. An insulating air layer S is defined between an inner circumferential surface of the cylindrical portion 7b and an outer circumferential surface 6c of the intermediate portion 6d.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a subchamber structure of an engine.

(Prior Art) Conventionally, an engine is known in which a sub-chamber forming member is fitted into a recessed portion of a cylinder head, thereby forming a sub-chamber that communicates with a main combustion chamber through a nozzle hole.

For example, in Japanese Utility Model Application Publication No. 2.20, a mouthpiece forming an auxiliary chamber is press-fitted into a recessed part of the cylinder head, and a heat insulating air layer is formed between the mouthpiece and the cylinder head. In the structure that forms a gap, a gap is formed between the mouthpiece and the cylinder head to solve the problem that the cylinder head plastically deforms and cracks occur due to thermal expansion of the mouthpiece during engine operation. To,
It is described that a cylindrical collar having an annular flange is fitted and the outer circumferential surface of the collar is brought into close contact with the cylinder head, and seven flanges are brought into close contact with the lower part of the mouthpiece to form a heat insulating air layer.

However, in the structure described above, the mouthpiece and collar are press-fitted to form an insulating air layer, so the sealing performance of the insulating air layer is not sufficient, and there is a problem that it is difficult to expect a sufficient insulation effect. be.

(Object of the Invention) In view of the above points, the present invention provides an engine pre-chamber structure that improves the sealing performance of the heat-insulating air layer formed around the pre-chamber and enhances the heat insulation effect of the heat-insulating air layer. The purpose is to

(Structure of the Invention) In order to achieve the above-mentioned object, the present invention includes a sub-chamber component fitted into a recess of a cylinder head, which is a metal chamber having a cylindrical outer peripheral surface and forming a sub-chamber therein. parts and
a metal sleeve having a cylindrical portion and located outside the chamber member; one end of the sleeve is fixed to the chamber member, while the other end is slidable in the axial direction with respect to the chamber member; and a sealing means between the chamber member and the chamber member;
It is characterized in that the cylindrical outer peripheral surface of the member and the cylindrical portion of the sleeve are positioned with a predetermined gap forming a heat insulating air layer.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

In the diesel engine shown in FIG. 1, a sub-chamber forming member 2 is fitted into a recess 1a of a cylinder head 1, and a sub-chamber 5 is formed which communicates with a main combustion chamber 3 through a nozzle hole 4. The sub-chamber component 2 includes a metal sleeve 7 disposed outside a metal chamber member 6.

The chamber member 6 has a hollow shape with a subchamber 5 formed therein, is made of a heat-resistant metal (for example, Inconel), has a hemispherical upper surface 6a, and has a mounting hole 9 for the glow plug 8 that opens into the subchamber 5. The fuel injection nozzle 10 includes an upper part 6b in which the injection hole 11 of the fuel injection nozzle 10 is formed, an intermediate part 6d having a cylindrical outer peripheral surface 6C, and a lower flange part 6e having a larger diameter than the intermediate part 6d.

The sleeve 7 has a cylindrical shape, is made of stainless steel, and has an upper flange portion 7a whose inner edge is electron beam welded to a stepped portion 6f at the upper end of the intermediate portion 6d of the chamber member B;
Cylindrical portion 7 extending vertically downward from the outer end edge of flange portion 7a
It consists of b. The lower end of this cylindrical portion 7b extends to the vicinity of the lower flange portion 6e of the chamber member B, and the intermediate portion 6d
It is shown that it contacts in the radial direction with the elastic sealing material 12 disposed on the step portion 6q at the lower end, and can slide in the axial direction with respect to the chamber member 6 while still in contact with it.

Further, the inner circumferential surface of the cylindrical portion 7b is located with a predetermined gap from the cylindrical outer circumferential surface 6C of the intermediate portion 6d of the chamber member B, and a heat insulating air layer S is formed between the two surfaces.

As a result, the heat insulating air layer S formed between the chamber member 6 and the sleeve 7 is almost completely sealed on the upper side by welding and on the lower side by the sealing material 12.

In addition, 16 is a cylinder block, 14 is a gasket, 1
5 is a positioning pole.

With the above configuration, a heat insulating air layer S is formed between the chamber member 6 and the sleeve 7 with good sealing performance, so that the heat insulation effect is enhanced and heat is prevented from escaping from the chamber member 6 to the cylinder head 1. This can be prevented, and warm-up and combustibility can be improved.

Furthermore, since the lower end of the sleeve 7 can slide in the axial direction with respect to the chamber member 6 while in contact with the sealing material 12, it is possible to absorb thermal deformation and the like without impairing the sealing performance. It is also possible to prevent the occurrence of

In the above embodiment, the lower end of the sleeve 7 is in contact with the sealing material 12, but as shown in FIG. It is also possible to provide a seal with an elastic sealing material 12 above the abutting portion.

(Effects of the Invention) Since the present invention is constructed as described above, it is possible to reliably seal the insulating air layer, absorb thermal deformation without impairing the sealing performance, and have a heat insulating effect due to the insulating air layer. can be increased. Moreover, since the structure is simple, it is easy to form a heat insulating air layer.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a sectional view showing the subchamber structure of an engine, and FIG. 2 is a sectional view of a main part of a modified example.

Claims (1)

[Claims] (1) In an engine in which a sub-chamber forming member is fitted into a recessed portion of a cylinder head to form a sub-chamber that communicates with a main combustion chamber through a nozzle hole, the sub-chamber forming member has a cylindrical outer peripheral surface and an inner a metal chamber member forming a sub-chamber;
a metal sleeve having a cylindrical portion and located outside the chamber member, one end of the sleeve being fixed to the chamber member, and the other end being slidable in the axial direction with respect to the chamber member; A sub-chamber structure for an engine, characterized in that a shielding means is provided between the chamber member and the cylindrical outer circumferential surface of the chamber member and the cylindrical portion of the sleeve with a predetermined gap between them.