JP2002309996A - Cooling structure for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent gas from staying in a through hole part formed in a gasket between a cylinder block and a cylinder head without lowering the warming up performance of an internal combustion engine. SOLUTION: A water hole 8 communicating with the interior of a water jacket 4 of the cylinder block 1 is opened to the upper face of the cylinder block 1. The through-hole 9 formed in the gasket 3 between the cylinder block 1 and the cylinder head 2 communicates with the water hole 8. A water hole 13 formed in the cylinder head 2 on the internal wall 6 side forming a cylinder bore 5 of the cylinder block 1 is opened downward so as to partially overlap with the through-hole 9. The communicating areas of the through-hole 9 and a water hole 13 are respectively set smaller than the communicating area of the through-hole 9 and water hole 8 and the open area of the through-hole 9 to the lower face of the cylinder head 2 excluding the water hole 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling structure for a water-cooled internal combustion engine, and more particularly to a mechanism having a cooling function desirable for an internal combustion engine.

[0002]

2. Description of the Related Art In a conventional internal combustion engine disclosed in Japanese Patent Application Laid-Open No. 2000-186615, a water hole communicating with a water jacket of a cylinder block is provided in a gasket.
A flat bottom surface of the cylinder head is exposed to the water jacket of the cylinder block through the water hole, and a bottom surface of the cylinder head close to the fuel injection valve is cooled by cooling water flowing in the water jacket of the cylinder block. However, in this case, the water hole of the gasket is completely closed at the top by the flat bottom surface of the cylinder head, so that gas such as air when cooling water is filled easily accumulates in the water hole. In other words, once the gas stays, there is a possibility that the essential cooling effect of the cooling water is obstructed.

As in the conventional case, it is conceivable to provide a hole on the cylinder head side in which the water hole communicates with the water jacket of the cylinder head. As the cooling water flow from the side to the cylinder head increases, the cooling water flow flowing through the water jacket of the cylinder block also increases, resulting in a decrease in the warm-up performance of the internal combustion engine at a cold start or the like. However, there is a problem that fuel efficiency and exhaust gas of the internal combustion engine are deteriorated.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to prevent gas from remaining in a through hole formed in a gasket between a cylinder block and a cylinder head without deteriorating the warm-up performance of an internal combustion engine. Is what you do.

[0005]

SUMMARY OF THE INVENTION Accordingly, a cooling structure for an internal combustion engine according to the present invention has a water hole formed in a cylinder block, which is opened on an upper surface of the cylinder block and communicates with a water jacket of the cylinder block. A water passage hole formed in the cylinder head and opening to the lower surface of the cylinder head and communicating with the inside of the cylinder head; and a through hole for a gasket sandwiched between the cylinder block and the cylinder head. The communication area between the through hole and the water hole is smaller than the communication area between the through hole and the water hole and the opening area of the through hole with respect to the lower surface of the cylinder head excluding the water hole. It is set as follows.

That is, the communication area between the through hole of the gasket and the water hole formed in the cylinder head is the communication area between the through hole and the water hole formed in the cylinder block, and
The cooling water flowing through the water jacket of the cylinder block relatively easily flows into the through-hole because it is set to be smaller than the opening area of the through-hole with respect to the lower surface of the cylinder head excluding the water-passing hole. Then, the lower surface of the cylinder head is cooled, and the temperature of the cooling water in the water jacket can be increased by receiving heat from the lower surface of the cylinder head. Since the flow of cooling water between the holes and the water holes is restricted, the temperature rise of the cooling water can be accelerated by suppressing the flow rate of the cooling water in the water jacket, and the warm-up characteristics of the internal combustion engine can be improved. In addition, the gas in the through hole is easily extracted to the cylinder head side by the water passage hole, and the gas is reliably prevented from staying in the through hole. It can be.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention shown in the drawings will be described by assigning the same reference numerals to equivalent parts. FIG. 1 shows a state in which a cylinder head 2 has been removed from an open deck cylinder block 1 of a water-cooled internal combustion engine, and a gasket 3 is normally held between an upper surface of the cylinder block 1 and a lower surface of the cylinder head 2. The lower side of FIG. 1 is the exhaust side, and the upper side of FIG. 1 is the intake side.

As shown in FIG. 2, the water jacket 4 of the cylinder block 1 is formed along the plurality of cylinder bores 5 between the inner wall 6 and the outer wall 7, while water formed on the cylinder block 1 is formed. The upper end of the hole 8 is continuously open to the upper surface of the cylinder block 1 so as to surround each of the cylinder bores 5, and communicates with the lower water jacket 4. Through holes 9, 10, 11, 12 communicating with each other are formed intermittently, and further, water flow holes 13, 14, 15, 16, 17 formed intermittently in cylinder head 2 have lower ends of cylinder head 2 respectively. With an opening on the bottom,
The upper part communicates with a water jacket (not shown) of the cylinder head 2.

In this case, the through hole 9 and the water hole 13 are arranged between the adjacent cylinder bores 5, so that the water hole 13 is arranged so as to be close to the inner wall 6 of the cylinder block 1. 8, the lower opening of the through hole 9 and the water hole 13, the upper opening of the water hole 8, the lower opening of the through hole 10 and the water hole 14, the upper opening of the water hole 8, the through hole 1
1 and the lower opening of the water hole 16, the upper opening of the water hole 8, and the lower opening of the through hole 12 and the water hole 17, respectively.
At the top and bottom as indicated by hatching.

The cylinder block 1 has a cooling water inlet 2 connected to a discharge port of a water pump (not shown).
The cooling water supplied to the cooling water inlet 20 is supplied from the inlet 21 to the water jacket 4, and passes through a head-side inlet (not shown) formed in the gasket 3 and the cylinder head 2. Cylinder head 2
The cooling water flow rate in the water jacket 4 is suppressed because the flow path cross-sectional area to the cylinder head 2 side is set to be much larger than the flow path cross-sectional area to the cylinder block 1 side. Thereby, the warm-up performance is enhanced.

In the above device, the exhaust side of the cylinder block 1 where the temperature is likely to be high is the upper opening of the water hole 8, the through hole 10, and the lower opening of the water hole 14 provided between two exhaust ports (not shown). Are relatively large and vertically overlap, so that cooling water flows relatively easily from the water jacket 4 of the cylinder block 1 to the cylinder head 2 side, so that the exhaust side can be cooled relatively well. In contrast, cylinder block 1
On the intake side, even though the upper opening of the water hole 8 and the lower openings of the through hole 11 and the water hole 16 overlap vertically, the cross-sectional area of the through hole 11 is very small. Cylinder head 2 from inside water jacket 4
The flow of the cooling water to the side is substantially restricted, but the gas in the water hole 8 can be easily drawn out to the cylinder head 2 side when the cooling water is filled or the like.

On the other hand, the upper opening of the water hole 8, the lower hole of the through hole 9 and the lower hole of the water hole 13 are vertically overlapped. As can be clearly understood from FIG.
The communication area 3 is much smaller than the communication area between the through hole 9 and the water hole 8 and the opening area of the through hole 9 with respect to the lower surface of the cylinder head 2 excluding the water hole 13. 2-3m considering the viscosity of cooling water
The size is set to be about m.

Therefore, the cooling water flowing in the water jacket 4 of the cylinder block 1 flows into the through hole 9 relatively easily, and the cylinder head 2 in contact with the through hole 9
Of the through hole 9 can be effectively cooled.
Of the cooling water in the water jacket 4 through the water holes 13 into the water jacket of the cylinder head 2 is moderately restricted. Since the temperature rise of the cooling water in the water jacket 4 can be accelerated at the time of a cold start of the engine, etc., the warm-up characteristics of the internal combustion engine can be improved. Can be easily realized.

In addition, when the cooling water is filled, the through hole 9 and the water passage hole 13 communicate with each other, so that the gas in the through hole 9 can always be easily extracted to the cylinder head 2 side. There is a characteristic that can be reliably prevented from staying in the through hole 9.

Moreover, the flow rate of the cooling water in the water jacket 4 is relatively small on the inner wall 6 side of the cylinder block 1 and relatively large on the outer wall 7 side, but the water passage hole 13 is close to the inner wall 6 of the cylinder block 1. Since the communicating portion between the through hole 9 and the water passage hole 13 is closer to the inner wall 6 of the cylinder block 1, the water passage hole 13 is arranged close to the outer wall 7 of the cylinder block 1. As compared with the case of the above, there is an advantage that the flow rate of the cooling water flowing to the cylinder head 2 side through the water passage hole 13 is reduced, and the deterioration of the warm-up characteristic can be easily suppressed.

The cooling water in the water jacket 4 is easily locally heated on the inner wall 6 side of the cylinder block 1, that is, on the cylinder bore 5 side, but the water hole 13 is close to the inner wall 6 of the cylinder block 1. And since it is arrange | positioned between the adjacent cylinder bores 5, the cooling water superheated along the inner wall 6 of the cylinder block 1 and / or between the adjacent cylinder bores 5 flows through the water holes 1 by natural convection.
Thus, the cylinder block 1 can be efficiently extracted to the cylinder head 2 side through the cylinder block 3, so that the cylinder block 1 can be appropriately prevented from overheating.

Furthermore, since the through hole 9 of the gasket 3 is arranged between the cylinder bores 5 having a particularly high heat load,
The water jacket 4 passes through the through holes 9 and the water holes 13.
The cooling water in the through-hole 9 is controlled by the cooling water in the through-hole 9 while appropriately suppressing the flow rate of the cooling water flowing from the inside to the cylinder head 2 side.
The lower surface of the cylinder head 2 contacting inside is effectively cooled,
From this aspect, overheating of the cylinder head 2 can be suppressed.

Further, since the through hole 9 and the lower opening of the water hole 13 partially overlap vertically, the communication area between the through hole 9 and the water hole 13 can be set to be extremely small. In addition, it is not necessary to form a special thin water passage hole in the cylinder head 2, and the cross-sectional area of the water passage hole 13 can be formed to an appropriate size. There are advantages.

However, as shown in FIG. 3, although the lower opening of the water passage hole 13 vertically overlaps with the through hole 9, the water passage hole 13 itself may be made thin in the cylinder head 2. Therefore, it is possible to achieve a certain effect.

In each of the above embodiments, the cooling water discharged from the water pump is once supplied to the cylinder block 1 and then supplied to the cylinder head 2.
As shown in FIG. 4, the cooling water is supplied to the water pump 3.
0 to the cylinder head 2 and is supplied to the cylinder block 1 from the cylinder head 2 side. When the temperature of the cooling water in the cylinder block 1 is high, the amount of the cooling water flowing out of the cylinder block 1 is controlled by a flow control valve. The structure is controlled by 31 and the other structure may be the same as that of the above embodiment. However, 32 is a radiator, 3
Reference numeral 3 denotes a thermostat, and reference numeral 34 denotes a cooling water bypass passage. In this case, contrary to the above-described embodiments, the cooling water passes through the water hole of the cylinder head 2, the through hole of the gasket 3, and the water hole of the cylinder block 1 sequentially from the cylinder head 2 side. As a result, the flow of the cooling water in the cylinder block 1 can be suppressed while efficiently cooling the space between the bores, which is likely to be high in temperature, and the lower surface of the cylinder head 2 when the engine is cold started. The heat is easily transferred to the cooling water in the cylinder block 1 from above, so that the temperature of the cooling water in the cylinder block 1 can be increased at an early stage, and the warm-up performance can be improved.

Although each of the above embodiments relates to an open deck type cylinder block, a closed deck type cylinder block is constructed in the same manner as each of the above embodiments, so that it is equivalent to each of the above embodiments. Needless to say, it is possible to achieve the function and effect of the above.

[0022]

In the cooling structure for an internal combustion engine according to the present invention, the cooling water flowing through the water jacket of the cylinder block relatively easily flows into the through hole of the gasket, and the lower surface of the cylinder head is removed. While cooling can be performed, the flow of cooling water is restricted between the through hole and the water passage hole, and it is possible to enhance the warm-up characteristics of the internal combustion engine, thereby improving fuel efficiency of the internal combustion engine and harmful components of exhaust gas. Reduction can be easily realized, and at the same time, the gas in the through-hole can be easily extracted to the cylinder head side by the water-through hole, and can reliably be prevented from staying in the through-hole. There is a characteristic.

[Brief description of the drawings]

FIG. 1 is a top view of a main part according to an embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional view taken along line II-II of FIG.

FIG. 3 is an enlarged longitudinal sectional view of a main part according to another embodiment of the present invention.

FIG. 4 is a cooling water path diagram in another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Cylinder head 3 Gasket 4 Water jacket 5 Cylinder bore 6 Inner wall 7 Outer wall 8 Water hole 9, 10, 11, 12 Through hole 13, 14, 15, 16, 17 Water hole 30 Water pump

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02F 11/00 F02F 11/00 BF Term (Reference) 3G024 AA06 AA21 AA36 CA05 DA18

Claims (4)

[Claims] 1. A water hole formed in a cylinder block and opening on an upper surface of the cylinder block and communicating with a water jacket of the cylinder block, a water hole formed on a cylinder head and opening on a lower surface of the cylinder head, and A water hole communicating with the inside of the cylinder head, and a through hole of a gasket sandwiched between the cylinder block and the cylinder head, wherein a communication area between the through hole and the water hole is the through hole. A cooling area of the internal combustion engine, which is set to be smaller than a communication area between the through hole and the water hole and an opening area of the through hole with respect to a lower surface of the cylinder head excluding the water hole. 2. The cooling structure for an internal combustion engine according to claim 1, wherein a communicating portion between said through hole and said water passage hole is disposed near an inner wall of said cylinder block. 3. The cooling system for an internal combustion engine according to claim 1, wherein said water jacket is provided along a row of cylinder bores of said cylinder block, and said through hole and said water passage hole are arranged in the vicinity between adjacent cylinder bores. Construction. 4. The cooling structure for an internal combustion engine according to claim 1, wherein the opening of the water passage hole partially overlaps the through hole.