JPH07127519A - Water jacket structure of internal combustion engine - Google Patents

Abstract

PURPOSE:To reduce the friction loss by suppressing cooling of both the thrust and anti-thrust sides while the area between cylinder bores 4 having a high thermal load is cooled in good workmanship. CONSTITUTION:A water gallery 13 is provided at the outer wall part of a cylinder block 1 and is put in communication with a water jacket 5 through communication holes 21 furnished in cylinders. Each communication hole 21 is arranged offset toward the engine front from the center of cylinder bore 4 and is directed to the inter-bore area. The water jacket 5 has a deeper bottom 5a at these inter-bore areas and in the part with the opening for each communication hole 21, while the parts on the thrust side and anti-thrust side are formed with shallow bottom 5b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water jacket structure in a cylinder block of an internal combustion engine, and more particularly to an improvement of the water jacket structure in which cooling water is introduced into each cylinder through a water gallery provided on the outer wall of the cylinder block. .

[0002]

2. Description of the Related Art In a cylinder block of a multi-cylinder internal combustion engine, a water jacket formed so as to surround each cylinder bore is continuous in the front and rear. Generally, the bottom of each water jacket has the same depth. Has been formed.
When introducing cooling water into each cylinder through a water gallery provided on the outer wall of the cylinder block, a communication port that connects the water gallery and the water jacket is arranged at the bottom of the water jacket. ing. In particular, this communication port is generally formed as an opening toward the center of the cylinder bore.

In Japanese Utility Model Laid-Open No. 1-159159, a water gallery is not provided, but the depth of the bottom of the water jacket is partially changed in order to improve the cooling performance of each part of the cylinder bore. Is disclosed. Specifically, both side portions of the connecting portion of the cylinder wall forming each cylinder bore and portions in the thrust and anti-thrust directions are deep bottom portions, and the remaining portion, that is, a portion inclined by about 45 ° with respect to the cylinder row direction, is formed. It has a shallow bottom.

[0004]

However, if the thrust and anti-thrust water jackets are deep-bottomed as described above, the surface of the cylinder bore in this portion is excessively cooled, resulting in a large friction loss due to an increase in oil viscosity. There is a problem that it occurs. In particular, when combined with a water gallery type, low temperature cooling water is supplied from the communication port toward one of the thrust and anti-thrust sides that have become the deep bottom, so friction loss is further increased. Become. Also,
Relatively, the cooling between the cylinder bores tends to be insufficient.

[0005]

Therefore, according to the present invention, a water jacket is formed inside the cylinder block so as to surround the cylinder bore, and a water gallery is formed on the outer wall portion of the cylinder block along the cylinder row direction. In a water jacket structure of an internal combustion engine in which a communication port communicating with the water jacket bottom is formed for each cylinder bore from this water gallery,
The communication port is offset from the center of the cylinder bore in one of the cylinder row directions so as to be formed adjacent to the cylinder head bolt boss portion, and the portion between the cylinder bores of the water jacket and the communication port opening portion connected to this are relatively downward. It is characterized in that it has a deep bottom part extending toward the bottom and the part on the thrust and anti-thrust sides is a relatively shallow bottom part.

[0006]

The cooling water supplied to the water gallery by the water pump flows into the water jacket through the communication port provided for each cylinder. By arranging the communication port as described above, the cooling water is It is introduced mainly in the area between cylinder bores. Moreover, since the portion between the cylinder bores and the communication port opening portion are deep bottom portions,
The portion between the cylinder bores where the heat load is high is sufficiently cooled.
Further, since the thrust and anti-thrust side portions are shallow bottom portions, and the cooling water flowing in from each communication port does not hit so strongly, cooling is suppressed and friction loss is reduced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

1 to 6 show an embodiment in which the present invention is applied to a cylinder block 1 of a V-type 8-cylinder internal combustion engine.

The cylinder block 1 is integrally cast from cast iron, aluminum alloy or the like, has left and right banks 2 and 3, as shown in FIGS. 2 and 3, and has four cylinder cylinder bores 4 each. Is formed and surrounds these cylinder bores 4,
A water jacket 5 is formed for each bank 2, 3. A liner 6 is mounted on the inner circumference of each cylinder bore 4 in a dry liner form. Also, cylinder block 1
A skirt portion 7 is formed in the lower portion, and a bulkhead 8 is provided so as to partition the inside thereof to form a main bearing portion 9. 2 is a cross section taken along the center of the cylinder bore 4 of one bank 2, and FIG. 3 is the other bank 3
The cross-sections along the center of the cylinder bore 4 are shown.

The water jacket 5 is formed by a core at the time of casting. The upper deck 10 on which a cylinder head (not shown) is mounted is a so-called closed deck, and a large number of openings are formed in the upper deck 10. It communicates with a cylinder head side water jacket (not shown) through the communication hole 11. The outer surface of the cylinder block 1 is provided with an opening for supporting the core and discharging core sand, which is closed by a separate plug 12.

A water gallery 13 is formed on the outer wall portion of the cylinder block 1 between the V banks in the cylinder row direction. This water gallery 13
Is formed in the shape of an elongated passage by a core, is independently provided for each of the left and right banks 2 and 3, and is formed at a height position corresponding to the lower portion of the cylinder bore 4.
2 and 3, reference numeral 14 denotes a main oil gallery, and 15 denotes an oil passage extending from the main oil gallery 14 to the cylinder head side.

FIG. 1 shows a cross section taken along the line AA in FIG. 2. As shown in FIG. 1, the water jacket 5 surrounds the four cylinder bores 4 in the front-rear direction. Are formed continuously. Further, the cylinder wall 16 forming each cylinder bore 4 is formed separately in a cylindrical shape inside the water jacket 5, so that the water jacket 5 is formed by casting between the cylinder bores 4 as well. There is. Cylinder head bolt boss portions 17 are integrally formed with the left and right water jacket outer walls 18 at positions along the cylinder bores 4 and at both front and rear ends of the cylinder row. Bolt holes 19 are formed in the boss portions 17. ing. In FIG. 1, 2
Reference numeral 0 indicates an oil return passage.

The water jacket 5 has a water gallery 13 passing through the outer wall portion and a communication port 21 provided for each cylinder.
Through the. The communication port 21 is formed in a substantially rectangular shape in the outer wall 18 of the water jacket inside the bank which separates the water jacket 5 and the water gallery 13, and in particular, as shown in FIG.
It is arranged on one side in the cylinder row direction from the center, specifically, at a position offset toward the inlet 13a side of the water gallery 13,
It is in a state of being adjacent to the cylinder head bolt boss portion 17 between the cylinders. Further, as shown in FIG. 5, the height positions are respectively provided at positions corresponding to the lower part of the cylinder bore 4. In addition, in the water gallery 13,
Cooling water is supplied from the front end of the engine toward the rear of the engine by a water pump (not shown), but the water gallery 13 is gradually narrowed toward the rear end of the engine so that the flow velocity does not decrease on the downstream side. Correspondingly, the opening area of the communication port 21 of each cylinder is also set to be large on the front end side of the engine and small on the rear end side thereof, as shown in FIG.

The depth of the bottom of the water jacket 5 (the depth along the cylinder axis direction) is not uniform in each part, and there are a shallow part and a deep part.
Specifically, the portion between the cylinder bores 4 along the cylinder row direction and the portions at the front and rear ends are deep bottom portions 5a reaching near the lower end of the cylinder bores 4, and the communication ports 21 are continuously opened. The portion is also the deep bottom portion 5a. The remaining portion, that is, the water jacket 5 on the thrust and anti-thrust side of the cylinder bore 4 is
The shallow bottom portion 5b has a depth about half that of the deep bottom portion 5a. In FIG. 1, the formation range of the shallow bottom portion 5b is illustrated by cross hatching. Also, FIGS.
[Fig. 4] is a view of the bank 3 of the cylinder block 1 as viewed from the side, showing the positional relationship between the cylinder bore 4 and its center line L, and the deep bottom portion 5a and the shallow bottom portion 5b. As described above, since the deep bottom portion 5a and the shallow bottom portion 5b are provided, as shown in FIG. 4, in the cross section along the height position of the communication port 21, each communication port 21 has a depth between the cylinder bores 4. It is in a state of communicating only with the bottom portion 5a.

In the structure of the above-described embodiment, the cooling water supplied to the water gallery 13 from the front end side of the engine flows through the water gallery 13 toward the rear end side of the engine, and at the same time, from the communication ports 21 to the inside of the water jacket 5. And tries to flow substantially along the direction orthogonal to the cylinder row.
At this time, as shown in FIG. 4, the cooling water that has flowed in from each communication port 21 firstly has the deep bottom portion 5 a between the cylinder bores 4.
Flow toward the shallow bottom 5b. In particular, since the communication port 21 is arranged so as to be offset so as not to overlap the center line L of the cylinder bore 4 (see FIG. 5), the low-temperature cooling water is mainly introduced into the portion between the cylinder bores 4. Therefore, the cylinder bore 4 with a high heat load
The part in between is well cooled.

Further, at a portion on the thrust and anti-thrust side where a piston (not shown) is relatively strongly pressed, the water jacket 5 surrounding the cylinder bore 4 is a shallow bottom portion 5b, so that cooling is suppressed. Moreover, communication port 2
Since 1 is offset from the center toward the portion between the cylinder bores 4, the low temperature cooling water does not directly contact the thrust side or anti-thrust side portion of the cylinder wall 16. Therefore, on the thrust and anti-thrust sides, the inner wall surface of the cylinder bore 4 is kept at an appropriate high temperature state, and the friction loss due to the viscosity of the oil can be reduced.

[0017]

As is apparent from the above description, according to the water jacket structure of the internal combustion engine of the present invention, while satisfactorily cooling the portion between the cylinder bores having a high heat load,
It is possible to prevent excessive cooling on the thrust and anti-thrust side portions that have a great influence on friction, reduce friction loss, and thus improve fuel efficiency. In particular, it is possible to avoid overcooling due to the collision of the low temperature cooling water on the thrust and anti-thrust side portions, which are likely to occur when the water gallery type is adopted, and it is possible to achieve both uniform cooling performance of each cylinder and reduction of friction loss.

[Brief description of drawings]

FIG. 1 is a sectional view taken along the line AA of FIG. 2 showing an embodiment of a water jacket structure according to the present invention.

FIG. 2 is a transverse sectional view of the entire cylinder block of this embodiment.

FIG. 3 is a transverse sectional view of the entire cylinder block at different sectional positions.

FIG. 4 is a cross-sectional view of main parts taken along the line BB of FIG.

5 is a side view as seen from the direction of arrow C in FIG.

6 is a side view seen from the direction of arrow D in FIG.

[Explanation of symbols]

 1 ... Cylinder Block 4 ... Cylinder Bore 5 ... Water Jacket 5a ... Deep Bottom 5b ... Shallow Bottom 13 ... Water Gallery 17 ... Cylinder Head Bolt Boss 21 ... Communication Port

Claims (1)

[Claims] 1. A water jacket is formed inside a cylinder block so as to surround a cylinder bore, and
In the water jacket structure of the internal combustion engine, a water gallery is formed on the outer wall of the cylinder block along the cylinder row direction, and a communication port communicating with the bottom of the water jacket is formed in each cylinder bore from the water gallery. The port is offset from the center of the cylinder bore in one of the cylinder row directions so as to be formed adjacent to the cylinder head bolt boss portion, and the portion between the cylinder bores of the water jacket and the communication port opening portion connected thereto are extended relatively downward. A water jacket structure for an internal combustion engine, which has a deep bottom and a relatively shallow bottom on the thrust and anti-thrust sides.