JP3117537B2 - 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, one having a pair of intake holes for each cylinder is known as disclosed in, for example, Japanese Utility Model Laid-Open No. 55-132343. 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]

Since the sub-combustion chamber has a high pressure, it is important to ensure a sufficient sealing property around the sub-combustion chamber of the cylinder head. It is conceivable to fasten the cylinder block with bolts around the sub-combustion chamber, but as described above, a pair of intake ports are formed so as to extend from each intake hole to the sub-combustion chamber side of the cylinder row. In this case, there is a problem that it becomes difficult to secure a space for forming a bolt insertion hole around the auxiliary combustion chamber.

The present invention has been made in view of such circumstances, and has been made to improve the moldability of the cylinder head and to improve the sealing performance of the cylinder head in the vicinity of the sub-combustion chamber. It is an object of the present invention to provide a cylinder head structure of a sub-chamber type diesel engine capable of sufficiently securing the cylinder head.

[0006]

A cylinder head structure of a sub-chamber diesel engine according to the present invention is formed by bending a pair of intake ports so as to be separated from each other with the sub-combustion chamber interposed therebetween. A space for forming a bolt insertion hole is secured around the room, thereby achieving the above object.

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 to extend from each of the intake holes to a side of the cylinder row where the sub-combustion chamber is provided, and is formed so as to be separated from each other across the sub-combustion chamber; A bolt insertion hole through which a bolt for fastening the cylinder head to a cylinder block is formed at a position located on the side opposite to the exhaust hole with respect to the sub-combustion chamber therebetween. It is an butterfly.

[0008]

As described above, a pair of intake holes are formed at predetermined intervals in the cylinder row direction, and an intake port extending from each intake port is provided in the sub-combustion chamber of the cylinder row. Is formed so as to extend to the side, thereby improving the formability of the cylinder head, etc., but each intake port is bent and formed to be separated from each other with the sub-combustion chamber therebetween. Since a bolt insertion hole is formed at a position located on the side opposite to the exhaust hole with respect to the sub-combustion chamber between these intake ports, it is necessary to insert a bolt into this bolt insertion hole and fasten the cylinder head to the cylinder block. Thereby, it is possible to sufficiently secure the sealing property of the portion around the sub-combustion chamber of the cylinder head.

Therefore, according to the present invention, it is possible to improve the formability of the cylinder head, etc., and to sufficiently secure the sealing performance of the cylinder head around the sub-combustion chamber.

By inserting a bolt into the bolt insertion hole and fastening the cylinder head to the cylinder block,
Although the sealing performance around the sub-combustion chamber of the cylinder head can be sufficiently ensured, since the heat around the sub-combustion chamber becomes high, the bolts are thermally expanded accordingly. And it is inevitable that the thermal expansion deteriorates the sealing property to some extent. However,
As described in claim 2, if the bolt insertion hole is formed to be shorter than the bolt insertion hole formed in another part of the cylinder head, a relatively short bolt is used. Accordingly, deterioration of the sealing performance due to thermal expansion of the bolt can be minimized.

[0011]

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, FIG. 2 is a plan view thereof, and FIGS.
FIG. 4 is a sectional view taken along lines III-III and IV-IV of FIG.

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

As shown in FIG. 1, this cylinder head 1
2, a pair of intake holes 16 are formed at predetermined intervals in the cylinder row direction for each cylinder, and the exhaust holes 18 and the sub-combustion chambers 14 are sandwiched between the pair of intake holes 16. Are formed on both sides between the intake holes 16. 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 to a portion near the wall of the sub-combustion chamber 14 on the exhaust hole 18 side between the exhaust holes 18 and the respective intake holes 16. 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.

Each of the second cooling water passages 22 has a plug plug hole 24 formed at an end of the side of the cylinder row, and each of the second cooling water passages 22 is plugged with a plug. 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 the upper side of the sub-combustion chamber 14 and is bent so as to be separated from each other with the sub-combustion chamber 14 interposed therebetween. The intake ports 30 adjacent to each other between the cylinders constituting the cylinder row
The flange forming the upstream end of the intake is the integral flange 3
2 is shared. Note that the intake upstream end of the intake port 30 located at the end of the cylinder row is provided with a dedicated flange 3.
4.

The cylinder head 12 is fastened to a cylinder block (not shown) located below the sub-combustion chamber 14 between the pair of intake ports 30 and on the side opposite to the exhaust hole. A bolt insertion hole 36 through which a bolt (not shown) is inserted is formed.

In addition to the bolt insertion holes 36, bolt insertion holes 38 are formed at five locations around each cylinder of the cylinder head 12. Two of the five bolt insertion holes 38 also serve as the plug plug holes 24.

As shown in FIGS.
Is formed to be shorter (about half length) than the five bolt insertion holes 38 formed in other portions of the cylinder head 12. Next, the operation of the present embodiment will be described.

A pair of intake holes 16 are formed at predetermined intervals in the cylinder row direction, and an intake port 30 extending from each intake hole 16 is formed so as to extend toward the sub-combustion chamber 14 side of the cylinder row. As a result, the moldability of the cylinder head 12 is improved.
Each of the intake ports 30 is bent so as to be spaced apart from each other with the auxiliary combustion chamber 14 interposed therebetween. Bolt insertion holes 36 are formed in portions of the auxiliary combustion chamber 14 between the intake ports 30 which are located on the side opposite to the exhaust hole. Is formed, the bolts are inserted into the bolt insertion holes 36 to fasten the cylinder head 12 to the cylinder block, so that the sealing performance of the cylinder head 12 around the sub-combustion chamber 14 can be sufficiently ensured. .

Therefore, according to the present embodiment, it is possible to improve the formability of the cylinder head 12 and the like, and to sufficiently secure the sealing performance of the cylinder head 12 in the vicinity of the auxiliary combustion chamber 14. it can.

As described above, the bolts are inserted into the bolt insertion holes 36 to fasten the cylinder head 12 to the cylinder block, so that the auxiliary combustion chamber 14
Although sufficient sealing performance can be ensured in the peripheral portion, since the peripheral portion of the sub-combustion chamber 14 is heated to a high temperature, the bolt is thermally expanded accordingly. And it is inevitable that the thermal expansion deteriorates the sealing property to some extent. However, in this embodiment, since the bolt insertion holes 36 are formed shorter than the bolt insertion holes 38 formed in other parts of the cylinder head 12, relatively short bolts are used. Therefore, deterioration of the sealing performance due to thermal expansion of the bolt can be minimized.

[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 plan view showing the above embodiment.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a sectional view taken along line IV-IV of FIG. 2;

[Explanation of symbols]

 12 Cylinder head 14 Sub-combustion chamber 16 Intake hole 18 Exhaust hole 30 Intake port 36 Bolt insertion hole 38 Bolt insertion hole

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F02F 1/00-11/00

Claims (2)

(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. The sub-combustion chamber is formed so as to extend to the side of the sub-combustion chamber provided in the cylinder row, and is bent so as to be separated from each other with the sub-combustion chamber interposed therebetween. A cylinder head structure for a sub-chamber diesel engine, wherein a bolt insertion hole through which a bolt for fastening the cylinder head to a cylinder block is inserted is formed at a position located on an exhaust hole side. 2. The sub-chamber diesel engine according to claim 1, wherein the bolt insertion hole is formed to be shorter than a bolt insertion hole formed in another part of the cylinder head. Cylinder head structure.