JPH11270404A - Heat shield type cylinder head for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a cooling loss of combustion heat lost through a head jacket by recessing a part opposite to a combustion chamber, of a cylinder head from a contact face with a cylinder block to form the recessed part for mounting a heat insulation plate, and mounting the heat insulation plate in this mounting recessed part. SOLUTION: A heat shield plate 5 is mounted in a mounting recessed part formed on a part opposite to a combustion chamber, of a cylinder head 1. This heat insulation plate 5 is made of a heat-resisting heat insulating material such as the metal ceramic composite, the silicon nitride ceramic or the like. Further the heat shield plate 5 is larger than a cylinder bore diameter, and its peripheral edge 5b is kept into contact with a cylinder outer periphery 10 to be fixed thereto through a head gasket 3, which dispenses with a screw or the like, and prevents the escaping of the heat to the cylinder head 1 through the screw or the like. Whereby the cooling loss of the combustion heat lost through a head jacket 17 can be remarkably reduced, and the exhaust heat quantity can be effectively utilized by increasing the exhaust heat quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heat shield type cylinder head for an engine.

[0002]

2. Description of the Related Art Conventionally, ceramic heat shield type engines have been proposed. Although the engine is composed of a heat-shielding (insulating) material called ceramics having properties completely different from those of metals, it has not been put to practical use for the following reasons, for example.

[0003]

In a ceramic heat-insulating engine, the heat-insulating (insulating) effect becomes too high, and the effect is exerted on the intake air and the intake air amount is relatively short. Therefore, the output cannot be increased more than expected. On the other hand, in a normal engine, the cooling loss of combustion heat is too large in view of the heat balance of thermal energy. Incidentally, in a normal engine, assuming that the thermal efficiency is 30%, the heat loss due to exhaust gas is 30%, the heat loss due to cooling is 30%, and the heat loss due to heat radiation of the engine is 10%, the heat loss due to cooling is reduced. This can lead to an increase in the amount of work and, consequently, an increase in output and thermal efficiency.

[0004] The present invention has been made in view of such circumstances, and it is possible to improve the output of an engine by reducing the cooling loss of the combustion heat from the cylinder head without the heat shielding effect becoming too high. It is an object of the present invention to provide a heat shielding cylinder head capable of improving thermal efficiency.

[0005]

In order to solve the above-mentioned problems, the present invention is configured as follows. According to the first aspect of the present invention, the portion of the cylinder head 1 facing the combustion chamber is recessed from the contact surface 3 with the cylinder block 2 to form the mounting recess 4 of the heat shield plate 5. A plate 5 is mounted.

According to a second aspect of the present invention, there is provided a heat shield type cylinder head for an engine according to the first aspect, wherein a heat insulating packing 6 is interposed at least in a peripheral portion of the mounting recess 4 so that the mounting recess is provided. A heat shielding gap 7a is formed between the recessed wall 4a in the inner wall 4 and the heat shielding plate 5.

According to a third aspect of the present invention, there is provided a heat shield type cylinder head for an engine according to the first or second aspect, wherein the heat shield plate 5 has an intake / exhaust valve seat 9.
The inlets 8a and 8b of the valves 9a and 9b are opened, and the intake and exhaust valve seats 9a and 9b are closely fitted to the inlets 8a and 8b, and the heat shield plate 5 is formed larger than the cylinder bore diameter. The peripheral portion 5b is fixed by being brought into contact with the cylinder peripheral portion 10 via the head gasket 3.

[0008]

According to the present invention, the following functions and effects are obtained. (A) According to the first aspect of the present invention, the portion of the cylinder head 1 facing the combustion chamber is recessed from the contact surface 3 with the cylinder block 2 to form the mounting recess 4 of the heat shield plate 5. Since the heat shield plate 5 is installed in the inside 4, most of the heat conduction to the cylinder head 1 is blocked by the heat shield plate 5, and the cooling loss of the combustion heat lost through the head jacket is greatly reduced. Therefore, the amount of exhaust heat increases. Therefore,
The output of the engine can be improved by effectively using the increased amount of exhaust heat as, for example, heat energy for cogeneration or the like.

(B) According to the invention described in claim 2,
2. The heat shield cylinder head for an engine according to claim 1, wherein a heat insulating packing 6 is interposed at least in a peripheral portion of the mounting recess 4 to form a recessed wall 4a in the mounting recess 4.
Since the heat shield gap 7a is formed between the heat shield plate 5 and the heat shield plate 5, heat conduction to the cylinder head 1 is blocked by the heat shield plate 5 and more effectively blocked by the heat shield gap 7a. Therefore, the above effect (a) can be further enhanced.

(C) According to the invention described in claim 3,
3. The heat shield type cylinder head for an engine according to claim 1 or 2, wherein the fitting openings 8a.
By tightly fitting the intake / exhaust valve seats 9a and 9b to the intake / exhaust valve seat 8b, the heat shield plate 5 can be positioned, the heat shield plate 5 is formed larger than the cylinder bore diameter, and the peripheral edge 5b is formed by a head gasket. Since the heat shield plate 5 is fixed by being brought into contact with the cylinder peripheral portion 10 via the intermediate member 3, a screw or the like for fixing the heat shield plate 5 becomes unnecessary. Thereby, the heat of combustion that escapes to the cylinder head 1 through the fixing means such as screws can be minimized.

[0011]

Embodiments of the present invention will be described below in more detail with reference to the drawings. FIG. 1 shows a heat shield type cylinder head according to an embodiment of the present invention. FIG. 1 (A) is a longitudinal sectional view of a main part of the heat shield type cylinder head, and FIG. 1 (B) shows the heat shield type cylinder head. Bottom view from the combustion chamber side,
FIG. 2 is a longitudinal sectional view of a main part of a spark ignition type gas engine provided with the heat shield type cylinder head.

First, a spark ignition type gas engine will be briefly described. As shown in FIG. 2, in the spark ignition type gas engine, a gas supply means (not shown) is provided in an intake passage, and a lean mixture is supplied by a fuel gas supplied in an intake stroke, and a rich mixture is supplied by a fuel gas supplied in a compression stroke. Are formed in the combustion chamber 13 in layers. 2, reference numeral 14 denotes an exhaust valve, and reference numeral 15 denotes a spark plug.

Next, a heat shield type cylinder head which characterizes the present invention will be described. This heat shield type cylinder head
As shown in FIGS. 1 and 2, a portion of the cylinder head 1 facing the combustion chamber is recessed from a contact surface F with the cylinder block 2 to form a mounting recess 4 of a heat shield plate 5. The heating plate 5 is mounted. The heat shield plate 5 is
It is made of a heat-resistant heat insulating material such as a metal ceramic composite or silicon nitride ceramic. This is intended to significantly reduce the cooling loss of the combustion heat lost through the head jacket 17 by blocking the heat conduction to the cylinder head 1 with the heat shield plate 5.

Since the heat shield plate 5 can be mounted,
A heat-resistant glossy coating can be applied to the surface facing the combustion chamber. This heat-resistant glossy coating can further enhance the heat-shielding effect. Examples of the coating material include a heat-resistant material such as stainless steel for reflecting the radiant heat of the combustion flame, and chrome plating by mirror finish.

The peripheral portion in the mounting recess 4 and the spark plug 1
By interposing the heat insulating packing 6 around the mounting hole 16 of 5, a heat shield gap 7 a of 2 to 5 mm is formed in the ceiling between the recessed wall 4 a in the mounting recess 4 and the heat shield plate 5, A heat shield gap 7b of 1 to 3 mm is formed around the heat shield plate 5. These heat shield gaps 7a and 7b are
To further enhance the heat shielding effect. That is, the heat shielding effect is enhanced by the heat shielding plate 5 and the heat shielding gaps 7a and 7b, the amount of exhaust heat is increased, and the increased amount of exhaust heat is effectively used as heat energy for cogeneration or the like, thereby improving the output of the engine. Can be achieved.

The heat shield plate 5 has a valve seat 9 for intake and exhaust.
The fitting holes 8a and 8b of the a.9b and the mounting hole 16 of the spark plug 15 are opened, and the intake and exhaust valve seats 9a and 9b are tightly fitted to the fitting openings 8a and 8b, so that the heat shield plate is provided. 5 can be positioned at an appropriate position. In addition, the heat shield plate 5
As shown in FIGS. 1A and 2, the outer peripheral portion 5 b is formed to be larger than the cylinder bore diameter, and the peripheral portion 5 b is fixed to the outer peripheral portion of the cylinder (here, the cylinder liner) 10 via the head gasket 3. I have. This is a heat shield 5
It is intended to eliminate the need for a screw or the like for fixing the cylinder and to minimize the heat of combustion that escapes to the cylinder head 1 through the fixing means such as the screw.

In this embodiment, the piston body 1
1, a piston head 12 is detachably fixed. The reason why the piston head 12 is detachably fixed is that if the cylinder head 1 is removed, the piston head 12 can be assembled and removed, and the ease of cleaning and maintenance of the piston head 1 is considered. The piston main body 11 is formed in a cylindrical shape by integrally molding a ring land portion and a skirt portion with an aluminum material. The reason why the piston main body 11 is formed in a cylindrical shape is that the lower surface of the piston head 12 faces directly into the crankcase, and the contact area between the piston head 12 and the piston main body 11 is reduced. It is intended to minimize the heat conduction of the

The piston head 12 is also made of a heat-resistant and heat-insulating material such as a metal ceramic composite or silicon nitride ceramic. The piston head 12 has a peripheral lower end surface seated on a peripheral upper end surface of the ring land via an insulating packing 18 so as to be detachably fixed. This is because the piston head 12
It is intended to further reduce the heat conduction to the substrate. Further, a direct injection combustion chamber 13 is formed in the top surface of the piston head 12 so as to be recessed, and the heat resistant gloss coating is also applied to the combustion chamber surface of the direct injection combustion chamber 13 to further enhance the heat shielding effect. Can be enhanced.

The present invention is not limited to the above-described embodiment, and can be carried out by appropriately changing the specific shape of the heat shield plate. Further, the present invention is applicable to either a spark ignition engine or a compression ignition engine, and is not limited to a piston head made of a heat insulating material.

[Brief description of the drawings]

FIG. 1 shows a heat shield type cylinder head according to the present invention. FIG. 1 (A) is a longitudinal sectional view of a main part of the heat shield type cylinder head, and FIG. 1 (B) burns the heat shield type cylinder head. It is the bottom view seen from the room side.

FIG. 2 is a longitudinal sectional view of a main part of a spark ignition type gas engine provided with a heat shield type cylinder head according to the present invention.

[Description of Signs] 1 ... Cylinder head, 2 ... Cylinder block, F ... Contact surface, 3 ... Head gasket, 4 ... Mounting recess, 4a ... Recessed wall in the mounting recess, 5 ... Heat shield plate, 5b ... Heat shield Perimeter of the board,
6: heat insulating packing; 7a: heat shielding gap; 8a, 8b: fitting inlets of intake / exhaust valve seats; 9a, 9b: intake / exhaust valve seats; 10: cylinder periphery (cylinder liner).

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Dai Hayashida 1-1-1 Hama, Amagasaki-shi, Hyogo Prefecture Inside Kubota Fundamental Technology Research Institute, Inc. (72) Inventor Hirofumi Sekino 1-1-1, Hama, Amagasaki-shi, Hyogo Co., Ltd. Kubota Technology Research Institute

Claims (3)

[Claims] 1. A mounting recess (4) for a heat shield plate (5) is formed by recessing a portion of a cylinder head (1) facing a combustion chamber from a contact surface (F) with a cylinder block (2). A heat shield type cylinder head for an engine, wherein a heat shield plate (5) is mounted in the recess (4). 2. A heat shield type cylinder head for an engine according to claim 1, wherein a heat insulating packing (6) is interposed at least in a peripheral portion of said mounting recess (4), and said mounting recess (4) is provided in said mounting recess (4). A heat shield cylinder head for an engine, wherein a heat shield gap (7a) is formed between the recessed wall (4a) and the heat shield plate (5). 3. The heat shield type cylinder head according to claim 1, wherein said heat shield plate (5).
The inlet (8a) of the intake / exhaust valve seat (9a / 9b)
8b), and the intake / exhaust valve seats (9a / 9b) are tightly fitted into their fitting inlets (8a / 8b), and the heat shield plate (5) is formed larger than the cylinder bore diameter. The periphery (5b) was fixed by abutting the cylinder periphery (10) via the head gasket (3).
A heat shield type cylinder head for an engine.