JPH06221149A - Cylinder head of water-cooled multicylinder diesel engine - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a crack between an auxiliary combustion chamber and an exhaust gas valve port and between an intake air valve port and the exhaust gas valve port. CONSTITUTION:In cooling water rise holes 4a and 5a equivalent to a half number beginning with an uppermost stream side as seen from a jacket outlet 16, the hole diameters of the cooling water rise holes 4 and 5, corresponding thereto, of a gasket 3 are increased and those of remaining cooling water rise holes 4, 5, and 6 are decreased, and this way causes setting of the hole diameters of the cooling water rise holes 4a and 5a to a relatively high value. A portion between an auxiliary combustion chamber 15 and an intale air valve port 13b is cut off by a cutoff wall 21 and a portion between one boss part positioned above a position between cylinder bores 8 and 8 and the intake air valve port 13b is cut off by a cutoff wall 22. A pair of throttle boss parts 23 and 23 are protruded facing each other between a pair of boss parts for a head fixing bolt positioned above a position between the cylinder bores 8 and 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder head of a water-cooled multi-cylinder diesel engine, and more particularly to a structure of a cylinder head capable of enhancing a cooling effect on a portion having a large heat load.

[0002]

2. Description of the Related Art In a multi-cylinder diesel engine, particularly a sub-combustion chamber type diesel engine, which has multiple valves and has a high average effective pressure, the upper portion of each cylinder is strongly subjected to thermal stress and impact force due to explosion. Therefore, cracks are likely to occur at the corresponding portions of the cylinder head 10, and effective cooling is necessary to prevent such cracks from occurring.

A cooling device for a water-cooled multi-cylinder diesel engine is shown in FIG. In this cooling device, a cooling fan 31 and a radiator 32 are provided at the front of a diesel engine E, and cooling water W cooled by the radiator 32 is supplied from a water jacket 2 in a cylinder block 1 to a head in a cylinder head 10 by a water pump 33. The cylinder block 1 and the cylinder head 10 are cooled by pressure feeding to the jacket 12, and the cylinder block 10 and the cylinder head 10 are returned to the radiator 32 again.

FIG. 2 shows a conventional example of the cylinder head 10. FIG. 1A is a plan view of the gasket 3 interposed between the cylinder block 1 and the cylinder head 10.
(B) is a cross-sectional plan view of the main part of the cylinder head 10, and FIG.
Is a vertical sectional view taken along the line CC of FIG. 7B, FIG. 8D is a vertical sectional view taken along the line DD of FIG. 7B, and FIG. FIG.

In this cylinder head 10, two intake valve openings 13a, one exhaust valve opening 14a and a sub combustion chamber 15 are arranged above each cylinder bore 8, and each intake port 13 is located beside each sub combustion chamber 15. The exhaust ports 14 run in the direction crossing the bore arrangement direction and open to one side surface of the head, and each exhaust port 14 runs in the direction opposite to the intake port 13 and opens to the other side surface of the head. A head jacket 12 is formed in the cylinder head 10. The head jacket 12 communicates with a jacket outlet 16 that is open at one end of the cylinder head 10, and also includes an intake port 13, an exhaust port 14, and a sub-combustion chamber 15. It is composed of a plurality of branched passages 12a to 12f.

On the lower surface of the cylinder head 10, a plurality of cooling water rising holes 4a, 5a, 6a, 7a corresponding to the cooling water rising holes 4, 5, 67 of the gasket 3 are formed. The ascending holes 4a to 7a correspond to the intake port 1
Cooling water ascending hole 4a opened facing the lower passage 12b of No. 3
A cooling water rising hole 5a opened facing the outer passage 12c of the auxiliary combustion chamber 15, a cooling water rising hole 6a opened facing the lower passage 12a of the exhaust port 14, and the cylinder bore 8 of the gasket 3. The cooling water rising holes 7 and the cooling water rising holes 7a and 7a communicating with each other. Then, by appropriately setting the sizes of the cooling water rising holes 4, 5, and 6 of the gasket 3, the cylinder block 1 to the cylinder head 1
It is configured to set the flow rate of the cooling water rising to zero.

Of the cooling water rising holes 4, 5, 6, 7 of the gasket 3 (FIG. 2 (A)), other cooling water rising holes 4 except the cooling water rising holes 7 near the cylinder bore 8 5.6
In consideration of the water pressure of the cooling water W flowing into the cylinder block 1 on the lower side of the gasket 3, the hole diameter is gradually set larger as the distance from the inflow side (the left side of FIG. (A)) increases. Reference numeral 18 is a fixing bolt of the cylinder head 10, and 19 is a boss portion for the fixing bolt.

[0008]

In the above-described conventional example, the lower passage 12a and the upper passage 12b of the exhaust port 14 form a main passage while repeating merging and branching in the middle, and the lower passage 12a of the exhaust port 14 is formed. Cooling water rising hole 6a
The higher cooling water W forms one large flow through the main passage. Further, the cooling water W raised from the cooling water rising hole 5a opened in the outer passage 12c of the auxiliary combustion chamber 15
Forms another large flow in the lower passage 12b of the intake port 13 adjacent to the outer passage 12c in parallel with the main passage. These two streams then merge into one at the jacket outlet 16.

That is, in the above-mentioned conventional example, these two flows form the main flow of the cooling water W, and the flow to the other branch passages has a slow flow velocity. Therefore, the surroundings of the sub combustion chamber 15 and the space between the intake valve opening 13a and the exhaust valve opening 14a cannot be sufficiently cooled, and the space between the sub combustion chamber 15 and the exhaust valve opening 14a and the intake valve opening 13a are not formed. A crack is likely to occur between the exhaust valve opening 14a. The present invention has been made in consideration of such circumstances, and an object thereof is to prevent the occurrence of the cracks.

[0010]

Means for Solving the Problems In order to solve the above-mentioned problems, the means adopted by the present invention is a cylinder head of the above-mentioned conventional water-cooled multi-cylinder diesel engine, in which a lower passage 12b of the intake port 13 is provided. Of the cooling water rising holes 4a opened and the cooling water rising holes 5a opened facing the outer passage 12c of the auxiliary combustion chamber 15, the cooling water rising holes 4a corresponding to half from the most upstream side when viewed from the jacket outlet 16.・
5a increases the diameter of the cooling water rising holes 4 and 5 of the gasket 3 corresponding thereto and reduces the remaining cooling water rising holes 4 and 5 and 6 to reduce the cooling water rising holes 4a and 4a. 5a is set to have a relatively large hole diameter, and among the passages 12a to 12f, the outer passage 1 of the auxiliary combustion chamber 15 is
The flow of the cooling water W from 2c through the lower passage 12b of the intake port 13 is defined as the first flow 12A.
5 and the passage 12e between the exhaust valve ports 14a and the passage 12e between the two intake valve ports 13a and 13b.
Of the exhaust port 1 is defined as the second flow 12B.
The flow of the cooling water W passing through the lower passage 12a and the upper passage 12d of No. 4 is defined as a third flow 12C, and a cut-off wall 21 is provided between the auxiliary combustion chamber 15 and the intake valve port 13b to form the cylinder bore 8
The first flow 12A is formed by blocking the head fixing bolt boss portion 19 located on the upper side between 8 and the intake valve port 13b with the blocking wall 22, respectively. The first flow 12A is diverted from between the portion 19 and the auxiliary combustion chamber 15 to be merged with the second flow 12B, and a pair of head fixing bolt boss portions 19 located above the cylinder bores 8 and 8 are provided. The gist is that the pair of throttle boss portions 23, 23 are provided so as to face each other between 19 to project so as to regulate the diversion of the second flow 12B at the merging portion. .

[0011]

According to the present invention, half the cooling water rising holes 4a, 5a from the most upstream side as viewed from the jacket outlet 16 are the cooling water rising holes 4, 5 of the gasket 3 corresponding thereto. By increasing the hole diameter of the cooling water and decreasing the remaining cooling water rising holes 4, 5, and 6
The diameters of a and 5a are set to be relatively large, and the cooling water W discharged from these cooling water rising holes 4a and 5a is divided into two. That is, one is the outer passage 1 of the auxiliary combustion chamber 15.
2c forms a first flow 12A passing through the lower passage 12b of the intake port 13, and the other flows at a high flow rate between the auxiliary combustion chamber 15 and the head fixing bolt boss portion 19 and the second flow 1A.
Merge into 2B.

The first flow 12A has a cut-off wall 21 between the auxiliary combustion chamber 15 and the intake valve port 13b, and the cylinder bore 8 is closed.
It is formed by blocking the head fixing bolt boss portion 19 located on the upper side between 8 and the intake valve port 13b with the blocking wall 22. Further, between the pair of head fixing bolt bosses 19 and 19 located on the upper side between the cylinder bores 8 and 8, a pair of throttle bosses 23 and 23 are provided.
The second flow 12
Dividing of B at the confluence is regulated. As a result, the cooling water W flows at a high flow velocity through the passage 12f between the auxiliary combustion chamber 15 having a large heat load and the exhaust valve port 14a.

Next, a part of the cooling water W forming the second flow 12B is split on the upstream side of the two intake valve openings 13a and 13b, and the intake valve opening 13a and the exhaust valve opening 14 having a high heat load.
It passes through a and joins with the third flow 12C. As a result, around the auxiliary combustion chamber 15 having a large heat load and the intake valve port 1
3a and the exhaust valve opening 14a can be sufficiently cooled, and the space between the auxiliary combustion chamber 15 and the exhaust valve opening 14a and the intake valve opening 1
It is possible to effectively prevent the occurrence of cracks between 3a and the exhaust valve opening 14a.

[0014]

Embodiments of the present invention will now be described in more detail with reference to the drawings. FIG. 1 shows a cylinder head 10 according to an embodiment of the present invention, and FIG. 1A is a plan view of a gasket interposed between the cylinder block and the cylinder head.
FIG. 2B is a cross-sectional plan view of the main part of the cylinder head, and FIG.
Is a vertical sectional view taken along the line CC of FIG. 7B, FIG. 8D is a vertical sectional view taken along the line DD of FIG. 7B, and FIG. FIG. The basic structure of the cylinder head 10 is the same as that of the conventional cylinder head (FIG. 2), and the same members are designated by the same reference numerals to omit redundant description.

The characteristic structure of the present invention will be described below. As shown in FIG. 1, the cylinder head 10 has a cooling water rising hole 4a opened facing the lower passage 12b of the intake port 13 and a cooling water rising opened facing the outer passage 12c of the auxiliary combustion chamber 15. The hole 5a is opened at a position farthest from the exhaust valve opening 14a, and these cooling water rising holes 4a are formed.
Of the a. 5a, half of the cooling water rising holes 4a, 5a from the most upstream side as seen from the jacket outlet 16 have the corresponding cooling water rising holes 4, 5 of the gasket 3 enlarged, and The remaining cooling water rise holes 4, 5, 6
Is a hole having a small degree of air bleeding, so that the cooling water rising holes 4a and 5a are set to have a relatively large diameter.

In the vicinity of the sub-combustion chamber 15, a larger amount of cooling water W is discharged from the cooling water rising holes 4a, 5a on the upstream side, so that the first flow 12A, the second flow 12B, and the third flow 12A. This is for facilitating the formation of the flow 12C. Also, FIG.
As shown in (B), the auxiliary combustion chamber 15 and the intake valve port 13b
Is a blocking wall 21, and between the head fixing bolt boss 19 located on the upper side between the cylinder bores 8 and the intake valve port 13b is a blocking wall 22. As a result, the first flow 12A is diverted from between the boss portion 19 and the auxiliary combustion chamber 15 and merges with the second flow 12B.

Further, a pair of head fixing bolt boss portions 19 and 19 located above the cylinder bores 8 and 8.
A pair of aperture boss portions 23, 23 are provided so as to face each other and protrude. This regulates the diversion of the second flow 12B at the merging portion to form the second flow 12B.
Is the passage 12f between the auxiliary combustion chamber 15 and the exhaust valve port 14a.
Flow at a faster flow rate.

As described above, according to the present invention, the passage 1
Of the 2a to 12f, the cooling water W flows from the outer passage 12c of the auxiliary combustion chamber 15 through the lower passage 12b of the intake port 13 to the first flow 12A, the auxiliary combustion chamber 15 and the exhaust valve port 1.
4a and passage 12f and two intake valve openings 13a.1
A second flow 12B passing through the passage 12e between the 3b and a third flow 12C passing through the lower passage 12a and the upper passage 12d of the exhaust port 14 is formed. These three flows merge at the jacket outlet 16 and the radiator 32
Is returned to.

Cooling water W forming the first stream 12A
Is part of the auxiliary combustion chamber 15 and the head fixing bolt boss portion 1.
9 and joins the second stream 12B. Further, the split flow of the second flow 12B at the merging portion is regulated by the pair of throttle boss portions 23, 23, and the second flow 1
The cooling water W that forms 2B is the auxiliary combustion chamber 15 and the exhaust valve port 1
It flows through 4a at a high flow rate. In addition, a part of the cooling water W forming the second flow 12B is generated by the two intake valve openings 1
3a and 13b are branched on the upstream side, pass between the intake valve opening 13a and the exhaust valve opening 14a, and join with the third flow 12C.

As a result, the periphery of the auxiliary combustion chamber 15 having a high heat load and the space between the intake valve port 13a and the exhaust valve port 14a can be sufficiently cooled, and the space between the auxiliary combustion chamber 15 and the exhaust valve port 14a can be sufficiently cooled. It is possible to effectively prevent a crack from occurring between the intake valve opening 13a and the exhaust valve opening 14a. In addition,
The auxiliary combustion chamber 15 includes a pre-combustion chamber type and a swirl chamber type. Further, the cylinder head is not limited to the three-cylinder type, and it is not necessary to say that the four-cylinder type cylinder head can be appropriately modified and implemented.

[Brief description of drawings]

FIG. 1 shows a cylinder head according to an embodiment of the present invention,
1A is a plan view of a gasket interposed between the cylinder block and the cylinder head, FIG. 1B is a cross-sectional plan view of the main part of the cylinder head, and FIG. 2C is a C view of FIG. -C line vertical sectional view, the same figure (D) is the DD line vertical sectional view of the same figure (B)
(E) is a vertical sectional view taken along the line EE of FIG.

FIG. 2 shows a cylinder head according to a conventional example and is a view corresponding to FIG.

FIG. 3 is a schematic diagram of a cooling device for a water-cooled multi-cylinder diesel engine.

[Explanation of symbols]

W ... Cooling water, 3 ... Gasket, 4 ...
5 ・ 6 ... Cooling water rising hole of gasket, 4a ・ 5a ・ 6a ... Cooling water rising hole of cylinder head, 8 ... Cylinder bore, 10 ... Cylinder head, 12 ... Head jacket, 12A ... First flow of cooling water W, 12B ... second flow of cooling water W, 1
2b ... lower passage of intake port, 12C ... third flow of cooling water W, 12c ... outer passage of sub combustion chamber, 12d / 12e / 12f
... Cooling water passage, 13 ... Intake port, 13a ... Intake valve port, 14 ... Exhaust port, 14a ... Exhaust valve port, 15 ... Secondary combustion chamber, 16 ... Jacket outlet, 19 ... Head fixing bolt boss portion, 21 ... 22 ... Blocking wall, 23 ... Drawing boss part.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Mikumo 64 Ishizukitamachi, Sakai City, Osaka Prefecture Kubota Sakai Co., Ltd.

Claims (1)

[Claims] 1. Two intake valve openings (13a) (13b), one exhaust valve opening (14a) and a sub-combustion chamber (15) are arranged above each cylinder bore (8), and each intake port (13) ) Runs through the side of each sub-combustion chamber (15) in a direction that intersects the bore arrangement direction and opens on one side of the head, and each exhaust port (14) is in the direction opposite to the intake port (13). A multi-cylinder three-valve cylinder head 10 is formed by running and opening to the other side of the head, and a head jacket (12) is formed in the cylinder head (10).
(0) communicates with the jacket outlet (16) that opens at one end of the (0), and also intake port (13), exhaust port (14), auxiliary combustion chamber (15)
It is composed of a plurality of passages (12a to 12f) that are branched by, and a plurality of cooling water rising holes are formed on the lower surface of the cylinder head (10) corresponding to the cooling water rising holes (4, 5 and 6) of the gasket (3). Hole (4a
・ 5a ・ 6a) are opened, and these cooling water rising holes (4a ・ 5a ・ 6a) are
The cooling water rising hole (4a) opened to the lower passage (12b) of the intake port (13) and the cooling water rising hole opened to the outside passage (12c) of the auxiliary combustion chamber (15) ( 5a) and a cooling water rise hole (6a) opened facing the lower passage (12a) of the exhaust port (14), and the cooling water rise hole (4, 5 and 6) of the gasket (3) is formed. In the cylinder head of the water-cooled multi-cylinder diesel engine configured to set the flow rate of the cooling water (W) rising from the cylinder block to the cylinder head (10) by appropriately setting the size of the hole diameter of Cooling water rising hole (4a) facing the lower passage (12b) of the port (13) and cooling water rising hole (5a) facing the outer passage (12c) of the auxiliary combustion chamber (15) Out of the jacket
(16) From the most upstream side, half the cooling water rise holes
In (4a) and (5a), the diameters of the corresponding cooling water rising holes (4) and (5) of the gasket (3) are increased, and the remaining cooling water rising holes (4) and (5) ) ・ (6) is made smaller so that the cooling water rising holes (4a) ・ (5a) are set to a relatively large hole diameter, and the auxiliary combustion chamber (15) in the passages (12a-12f) is set. The flow of the cooling water W from the outside passage (12c) of the intake port (13) to the lower passage (12b) is defined as the first flow (12A), and the auxiliary combustion chamber (15) and the exhaust valve port ( 14a) and the passage (12f),
And the flow of the cooling water W passing through the passage (12e) between the two intake valve openings (13a) and (13b) is defined as the second flow (12B), and the lower passage of the exhaust port (14) ( The flow of the cooling water W passing through 12a) and the upper passage (12d) is defined as the third flow (12B), and the cutoff wall (21) is provided between the sub combustion chamber (15) and the intake valve port (13b).
By blocking the head fixing bolt boss (19) located on the upper side between the cylinder bores (8) and (8) and the intake valve port (13b) with the blocking wall (22), , The first flow (12A) is formed, and the first flow (12A) is diverted from between the boss portion (19) and the auxiliary combustion chamber (15) to form the second flow (12B). And a pair of throttle bosses (23) and (23) between the pair of head fixing bolt bosses (19) and (19) located above the cylinder bores (8) and (8). A cylinder head for a water-cooled multi-cylinder diesel engine, characterized in that it is configured so as to restrict the diverting of the second flow (12B) at the merging portion by facing and protruding.