JPS6140905Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a cylinder head gasket for an internal combustion engine that improves the cooling effect of the cylinder head by changing the size, position, flow rate distribution, etc. of the water passage holes in the gasket from those of conventional gaskets. . It is well known that increasing the compression ratio is effective in improving the fuel efficiency of internal combustion engines, but high compression ratios can cause knocking at high loads, especially at low and medium speeds. occurs, and this currently limits the ability to increase the compression ratio. Knocking occurs when unburned gas spontaneously ignites before the flame reaches the ignition source, such as from a high-temperature part of the combustion chamber wall at a location far from the ignition plug. It is effective to lower the temperature of the high temperature part of the chamber wall. The part of the combustion chamber wall that becomes particularly hot is the wall surface on the lower surface of the cylinder head, especially the wall surface near the exhaust port. Incidentally, the cylinder head is cooled by flowing cooling water through a water jacket formed inside the cylinder head. The cylinder head has an extremely complex shape because the intake port, exhaust port, spark plug, valve train, etc. are formed or installed therein, and the water jacket is inevitably formed into a complex shape as well. The cooling water flowing through it is
The current situation is that it has not been confirmed whether optimal and sufficient cooling is ensured so that the hottest part is cooled the most. Therefore, it is desired that the flow of cooling water be clarified to ensure a better flow of cooling water. Further, since the water pump for circulating the cooling water is driven mechanically in conjunction with the rotation of the crankshaft, there are problems in that the rotation speed decreases and knocking occurs. There is also the problem that a sufficient amount of cooling water cannot be circulated in the low to medium speed range. The purpose of this invention is to elucidate the cooling effect of the cylinder head due to the cooling water flowing through the cylinder head, and to achieve efficient cooling of the cylinder head with a limited amount of circulating cooling water. By allowing a small amount of water to flow to areas that do not require much cooling, and ensuring that a large amount of cooling water flows to areas that require high-temperature cooling, we aim to substantially improve cooling performance. The purpose of this is to reduce the temperature of the high temperature section and suppress knocking. In order to achieve this objective, in the cylinder head gasket for an internal combustion engine of the present invention, the sum of the cross-sectional areas of the water passage holes of the cylinder head gasket is made smaller than the sum of the cross-sectional areas of the discharge ports of the water pump for circulating cooling water. In other words, the circulating flow of cooling water is throttled at the cylinder head gasket, and the water passage holes that were previously located between the bores are eliminated to increase the throttling effect, thereby increasing the flow velocity at the gasket. In addition to providing sufficient momentum and directionality to flow a sufficient amount of cooling water to areas where it was previously difficult for the flow to reach, the plug By making the water passage holes on the side larger than the sum of the cross-sectional areas, a large amount of water can flow to the exhaust port side, which is a high-temperature area, allowing for efficient cooling. . Hereinafter, preferred embodiments of the cylinder head gasket for an internal combustion engine according to the present invention will be described with reference to the drawings. FIG. 1 shows a longitudinal section of an internal combustion engine equipped with the cylinder head gasket of the present invention. In the figure, 1 is a cylinder head, 2 is a cylinder block, and 3 is a cylinder head gasket interposed between the two. A water jacket 4 is formed on the cylinder head 1, and a water jacket 5 is formed on the cylinder block 2, and both water jackets 4 and 5 have water passage holes 6 formed in the cylinder head gasket 3. communicated with each other through. FIG. 2 schematically shows the structure of the cooling water circulation system in these devices. Cylinder head 1
The cooling water is led to the radiator 7, and the cooling water cooled by radiation from the radiator 7 is sent to the water pump 8.
It is sent back to the cylinder block 2, passes through the water passage hole 6 of the cylinder head gasket 3, and is circulated to the cylinder head 1. An example of the water passage hole 6 of the cylinder head gasket 3 is shown in FIG. In the same figure, the water passage hole 6 surrounded by a solid line and shaded is related to the present invention, the hole indicated by a broken line is a water passage hole of a conventional example shown for reference, and the two-dot chain line is a water passage hole 6 for cylinder head gas. This is a water passage hole provided in the cylinder head 1 in contact with the butt 3, and is also shown for reference. Therefore, the holes indicated by broken lines and the holes indicated by two-dot chain lines are not formed in the cylinder head gasket 3 itself of the present invention. As is clear from Fig. 3, in the conventional gasket, the water passage hole A, which was provided between the bores 9,
B, C, D, E, and F are omitted in the cylinder gasket of the present invention. In addition, the large water holes G and H provided at the right end in Figure 3
has been narrowed down to an extremely small size. In addition, among the water holes 6 provided in the center of the bore 9, water holes 6b, 6d, and 6 located on the exhaust side are also provided.
f and 6h are moved approximately 10 mm closer to the exhaust port 10 than the conventional water passage holes. This allows a large amount of cooling water to flow in the vicinity of the exhaust port 10, even though the water passage holes between the bores have been eliminated and the cross-sectional area of the water passage holes has been reduced. The total cross-sectional area of the water passage holes 6 of the cylinder head gasket 3 of the present invention is smaller than the cross-sectional area of the discharge port of the water pump 8. The breakdown of an example of the cross-sectional area of the water passage hole 6 is as shown in the following table.

[Table] As is clear from the table above, the sum of the cross-sectional areas of the water passage holes 6 near the No. 1 bore is 52 mm ² , which is the sum of the cross-sectional areas of the conventional water passage holes.
If 152mm ² is taken as 100%, it becomes 34% of that.
Similarly, No. 2 bore part has 88%, No. 3 bore part has 24%, and No.
It is 31% in the 4-bore section, and the total diameter is 451 mm ² , which is 32% of the conventional size. If this is expressed as an equivalent circular cross-sectional area, 451 mm ² corresponds to the cross-sectional area of a hole with a diameter of 24 mm, and the conventional 1391 mm ² corresponds to the cross-sectional area of a hole with a diameter of 42 mm. The discharge port cross section of water pump 8 is 26mm in diameter.
Therefore, the sum of the cross-sectional areas of the water passage holes 6 of the cylinder head gasket 3 of the present invention is smaller than the cross-sectional area of the discharge port of the water pump 8. Furthermore, in the gasket 3 of the present invention, the sum of the cross-sectional areas of the water holes 6b, 6d, 6f, and 6h located on the exhaust side is equal to the sum of the cross-sectional areas of the water holes 6a, 6c, and 6h located on the plug side.
It is larger than the sum of the cross-sectional areas of 6e, 6g, and 6i. This allows the high temperature side to be cooled more efficiently. For example, water holes 6a, 6b, 6c, 6d,
The diameters of 6e, 6f, 6g, 6h, 6i, 6j, and 6k are approximately 4 mm, 5 mm, 5 mm, 7 mm, and 6 in order, respectively.
mm, 9mm, 6mm, 10mm, 6mm, 10mm, 10mm. When the size of the circular hole 6 is determined in this way, the water passage holes 6b, 6 located on the exhaust side
The sum of the cross-sectional areas of d, 6f, 6h, and 6j, and the water holes 6a, 6c, 6e, 6g, and 6 located on the plug side.
The ratio to the sum of the cross-sectional areas of i and 6k is approximately 6:4. The above table is just an example, and from tests conducted with various cross-sectional areas of the water passage hole 6,
The improvement in the cooling effect described later can be obtained by changing the cross-sectional area as shown in the above table, and good cooling performance can be improved in the range where the sum of the cross-sectional areas of the water passage holes 6 is smaller than the cross-sectional area of the water pump 8 discharge ports. Can be seen. In the cooling system of an internal combustion engine configured as described above, cooling water is supplied to the cylinder head gasket section 3.
It is narrowed down, its flow speed is increased, momentum is increased, and directionality is also strengthened. For this reason, the cooling water
Cooling water flows vigorously to high-temperature areas that needed to be cooled, where in the past there was not enough cooling water. The water pump 8 circulates cooling water at a rate of about 40 to 170/min, and even in a low speed range, a sufficient amount of cooling water is ensured in the necessary parts. Furthermore, since a larger amount of cooling water is allowed to flow to the exhaust port side than to the plug side, areas around the exhaust port that have conventionally been particularly hot are efficiently cooled. FIG. 4 shows the combustion chamber wall temperature in the results of the cooling test. In addition, the numbers shown in parentheses in the same figure are also shown for reference as the combustion chamber wall temperature in the conventional example, and the numbers not enclosed in parentheses and the numbers shown in parentheses directly below The difference is the amount of reduction in combustion chamber wall temperature actually obtained by the present invention. Fig. 4 shows test examples for No. 1 bore and No. 4 bore, but the results for No. 2 bore and No. 3 bore are similar to these, and there is no significant difference. As is clear from the results shown in the figure, there was a significant decrease in the combustion chamber wall temperature by 15°C to 20°C, especially around the exhaust port 10, which had been at a high temperature. This drastic reduction in the combustion chamber wall temperature significantly suppresses the occurrence of knocking, making it possible to achieve a higher compression ratio and improve fuel efficiency. Furthermore, the ignition angle can also be advanced, and improvements in shaft torque and driving performance can also be achieved. FIG. 5 shows the extent to which the ignition advance angle is advanced by changing the size of the water passage hole, and FIG. 6 shows the extent to which the shaft torque is improved. As is clear from these figures, an ignition advance of 2 to 3 degrees can be obtained in the rotation range of 1600 to 2400 rpm, which is often used in practice, and the shaft torque is also 0.5 kg・
It can be improved by nearly m, that is, by nearly 5% compared to the conventional method. When using the cylinder head gasket for an internal combustion engine according to the present invention, the sum of the cross-sectional areas of the water holes is smaller than the cross-sectional area of the water pump discharge port, and the sum of the cross-sectional areas of the water holes located on the exhaust side is made smaller than the water pump discharge port cross-sectional area. By simply adopting an extremely simple and inexpensive method of making the water passage hole located on the plug side larger than the sum of the cross-sectional areas, it is possible to achieve a wide and efficient reduction in the combustion chamber wall temperature. The effect is extremely large from a practical point of view. In addition, as a result, knocking is suppressed as the combustion chamber wall temperature decreases, making it possible to improve fuel efficiency by increasing the compression ratio, and by advancing the ignition angle, shaft torque and drivability are improved. The obvious effect is that it is possible to improve the

[Brief explanation of drawings]

Figure 1 is a longitudinal sectional view of an internal combustion engine equipped with the cylinder head gasket of the present invention, Figure 2 is a schematic diagram of the cooling system of the internal combustion engine of Figure 1, and Figure 3 is a cylinder of the internal combustion engine of the present invention. A plan view of an example of a head gasket, Fig. 4 is a distribution diagram of combustion chamber wall temperature of an internal combustion engine equipped with the cylinder head gasket of the present invention, Fig. 5 is a diagram of ignition advance characteristics, and Fig. 6 is a diagram of shaft torque. It is a characteristic diagram. 3...Cylinder head gasket, 6...Water hole, 6a, 6c, 6e, 6g, 6i, 6k...Water hole on plug side, 6b, 6d, 6f, 6h, 6j
...Water hole on the exhaust side, 8...Water pump.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) The sum of the cross-sectional areas of the water passage holes from the cylinder block to the cylinder head bored in the cylinder head gasket is smaller than the discharge cross-sectional area of the water pump for circulating cooling water, and A cylinder for an internal combustion engine, characterized in that the water holes between the bores are eliminated, and the sum of the cross-sectional areas of the water holes located on the exhaust side is larger than the sum of the cross-sectional areas of the water holes located on the plug side. head gasket. (2) Scope of Utility Model Registration In the cylinder head gasket for an internal combustion engine according to claim 1, the sum of the cross-sectional area of the water hole located on the exhaust side and the cross-sectional area of the water hole located on the plug side. The ratio to the sum is approximately 6:
4.