JP3172251B2 - Cylinder head structure of subchamber diesel engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a cylinder head in a so-called sub-chamber diesel engine having a sub-combustion chamber.

[0002]

2. Description of the Related Art As one type of a sub-chamber type diesel engine, for example, as disclosed in Japanese Utility Model Laid-Open Publication No. 55-132343, a pair of intake holes is formed for each cylinder constituting a cylinder row. Things are known. As disclosed in the above-mentioned publication, the structure of the cylinder head in such a sub-chamber diesel engine is such that the exhaust hole and the sub-combustion chamber have both intake ports with the pair of intake ports interposed therebetween. Those formed on both sides between holes are known.

In such a structure of the cylinder head, the pair of intake holes are formed at predetermined intervals in the cylinder row direction, and an intake port extending from each intake hole is provided on the side of the cylinder row where the auxiliary combustion chamber is provided. In order to improve the moldability of the cylinder head and the like, it is preferable to form it so as to extend.

[0004]

However, when such a structure of the cylinder head is employed, a large number of intake ports are arranged in the cylinder row direction. In addition, there is a problem that the cylinder head becomes longer in the cylinder row direction.

The present invention has been made in view of such circumstances, and aims to improve the formability of a cylinder head in a sub-chamber diesel engine having a pair of intake holes for each cylinder. It is another object of the present invention to provide a cylinder head structure capable of reducing the size of the cylinder head.

[0006]

In the cylinder head structure of the sub-chamber diesel engine according to the present invention, the flange forming the intake upstream end of each intake port is shared between adjacent cylinders. It is intended to achieve the purpose.

That is, as described in claim 1, the structure of the cylinder head in the diesel engine having the sub-combustion chamber, wherein a predetermined interval is provided in the cylinder row direction for each cylinder constituting the cylinder row. A pair of intake holes are formed, and an exhaust hole and the sub-combustion chamber are formed on both sides between the pair of intake holes so as to sandwich the pair of intake holes. An intake port is formed so as to extend from each of the intake holes to the side of the sub-combustion chamber of the cylinder row, and intake upstream ends of these intake ports are bent and formed so as to be separated from each other; The intake air adjacent to each other between the cylinders
Together when the intake upstream end of the intake ports of each pair corresponding to holes are integrally formed in a single flange
Corresponding to the pair of intake holes in each of the cylinders.
The intake upstream end of the intake port is a different
It is formed on the flange .

[0008]

As described above, in each cylinder, the intake upstream end of each intake port formed to extend from each of a pair of intake holes to the side of the sub-combustion chamber of the cylinder row. When the intake ports are bent so as to be separated from each other and the intake upstream ends of the intake ports adjacent to each other between the cylinders are formed integrally with a single flange, a flange is provided for each intake port. , The overall length of the cylinder head can be reduced.

Therefore, according to the present invention, in a sub-chamber diesel engine in which a pair of intake holes is formed for each cylinder, it is possible to improve the formability of the cylinder head and the like. The head can be made compact.

[0010] In addition to the above configuration, as described in the second aspect, if the cross-sectional shape of the intake upstream end of each intake port is a vertically long and substantially rectangular shape, it is the same as a simple circular cross-sectional shape. After securing the cross-sectional area, the dimension of the flange in the direction of the cylinder row can be reduced, whereby the overall length of the cylinder head can be further reduced.

In addition to the above configuration, the cross-sectional shape of the intermediate portion of each intake port is vertically shorter than the cross-sectional shape of the upstream end portion of the intake port and is directed toward the sub-combustion chamber. The swelling shape makes it possible to smoothly change the cross-sectional shape between the intake hole having a generally circular cross-sectional shape and the intake upstream end having a vertically long substantially rectangular cross-sectional shape, thereby preventing a decrease in intake performance, and The intake air passing through the port can cool the portion around the sub-combustion chamber of the cylinder head.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a plan sectional view showing an embodiment of a cylinder head structure of a sub-chamber diesel engine according to the present invention, and FIG. 2 is a side view thereof.

As shown in these drawings, this cylinder head structure is a structure of a cylinder head 12 in a diesel engine having a sub combustion chamber 14.

In the cylinder head 12, a pair of intake holes 16 are formed at predetermined intervals in the cylinder row direction for each cylinder constituting the cylinder row.
An exhaust hole 18 and a sub-combustion chamber 14 are formed on both sides between the two intake holes 16 so as to sandwich the pair of intake holes 16 therebetween. Further, a first cooling water passage 20 is formed between the exhaust hole 18 and the sub-combustion chamber 14. The cylinder head 12 has a pair of first and second pairs extending from the side of the cylinder array and extending between the exhaust holes 18 and the respective intake holes 16 to a portion near the wall of the auxiliary combustion chamber 14 on the exhaust hole 18 side. Two cooling water passages 22 are formed. The pair of second cooling water passages 22 communicate with each other in the vicinity of the wall, and
The portion is formed so as to communicate with the first cooling water passage 20.

A plug plug hole 24 is formed at the end of each second cooling water passage 22 on the side of the cylinder row, and each of the second cooling water passages 22 is plugged with a plug in the plug plug hole 24. Is made. And each second
The cooling water passage 22 communicates with a cooling water introduction passage 26 in the vicinity of the plug hole 24.

The exhaust port 28 is formed so as to extend from the exhaust hole 18 to the side of the cylinder head 12 where the second cooling water passage 22 is provided, and the intake port 30 is formed from each of the intake holes 16 to the second cooling water passage. It is formed so as to extend to the side opposite to the side where 22 is disposed (that is, the side where the sub-combustion chamber 14 is disposed). The exhaust port 28 is connected to the pair of second cooling water passages 2.
It is formed so as to extend between the two. On the other hand, each intake port 30 is formed so as to pass through both upper sides of the sub-combustion chamber 14, and is bent so that its intake upstream end portions 30a are separated from each other. The intake upstream ends 30 a of the pair of intake ports 30 adjacent to each other between the cylinders are formed integrally with a single flange 32. The intake upstream end 30a of the intake port 30 located at the end of the cylinder row is provided with a dedicated flange 34.
Is formed.

As shown in FIG. 3, each of the intake ports 30
The cross-sectional shape of the intake upstream end portion 30a is vertically long and substantially rectangular, and the cross-sectional shape of the intermediate portion 30b of each of the intake ports 30 is vertically longer than the cross-sectional shape of the intake upstream end portion 30a. It is short and swells toward the sub-combustion chamber 14 side. FIG. 3 is a cross-sectional view of the intake port 30 located second from the left end of the cylinder row in FIG.

Next, the operation of the present embodiment will be described.

Each intake port 3 formed to extend from each of the intake holes 16 to the side where the sub-combustion chamber 14 of the cylinder row is provided.
The intake upstream ends 30a are bent so as to be separated from each other, and the intake upstream ends 30a of the intake ports 30 adjacent to each other between the cylinders are integrally formed on a single flange 32. So each intake port 3
The total length of the cylinder head can be reduced as compared with the case where a flange is provided for each zero.

Therefore, according to this embodiment, in the sub-chamber diesel engine in which a pair of intake holes 16 are formed for each cylinder, the formability of the cylinder head 12 can be improved. Thus, the cylinder head can be made compact.

Further, in this embodiment, since the cross-sectional shape of the intake upstream end portion 30a of each intake port 30 is a vertically long and substantially rectangular shape, the integral flange 32 is formed as compared with a simple circular cross-sectional shape. Of the cylinder head 12 in the cylinder row direction can be reduced.
Can be further shortened.

Further, in the present embodiment, the cross-sectional shape of the intermediate portion 30b of each intake port 30 is different from that of the intake upstream end 3
0a, the intake hole 16 having a circular cross-sectional shape and the intake upstream end portion 3 having a vertically long substantially rectangular cross-sectional shape.
In addition to smoothing the change in the cross-sectional shape between 0a and 0a, it is possible to prevent the intake performance from lowering, and to cool the vicinity of the sub-combustion chamber 14 of the cylinder head 12 by the intake air passing through the intake port 30.

[Brief description of the drawings]

FIG. 1 is a plan sectional view showing an embodiment of a cylinder head structure of a sub-chamber diesel engine according to the present invention.

FIG. 2 is a side view showing the above embodiment.

FIG. 3 is a sectional view of an intake port showing the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 Cylinder head 14 Subcombustion chamber 16 Intake hole 18 Exhaust hole 30 Intake port 30a Intake upstream end part 30b Intermediate part 32 Flange

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-124424 (JP, A) JP-A-57-176342 (JP, A) JP-A-59-93926 (JP, A) 35504 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F02F 1/00-1/42 F02M 35/104 F02B 1/00-23/10

Claims (3)

(57) [Claims] 1. A cylinder head structure in a diesel engine having a sub-combustion chamber, wherein a pair of intake holes is formed at predetermined intervals in the cylinder row direction for each cylinder constituting a cylinder row. With
An exhaust hole and the sub-combustion chamber are formed on both sides between the pair of intake holes so as to sandwich the pair of intake holes therebetween. For each of the cylinders, an intake port is formed from each of the intake holes. In addition to being formed so as to extend to the side of the sub-combustion chamber provided in the cylinder row, the upstream end of the intake port of each of these intake ports is
The cylinders are bent so as to be spaced apart from each other, and are opposed to the intake holes adjacent to each other between the cylinders .
A corresponding upstream end of each pair of said intake ports,
Together they are integrally formed on a single flange, before
The intake ports corresponding to the pair of intake ports for each cylinder.
The upstream end of the intake port of the air port is
A cylinder head structure for a sub-chamber diesel engine, characterized in that the cylinder head structure is formed in a cylinder. 2. The sub-chamber diesel engine cylinder head structure according to claim 1, wherein a cross-sectional shape of the intake upstream end of each of the intake ports is a vertically long and substantially rectangular shape. 3. A cross-sectional shape of an intermediate portion of each of the intake ports is vertically shorter than a cross-sectional shape of an upstream end portion of the intake and bulges toward the sub-combustion chamber. 3. A cylinder head structure for a sub-chamber diesel engine according to claim 2.