JPS6224745Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cylinder head cooling device that effectively cools a valve seat, an exhaust valve, and the vicinity thereof of an internal combustion engine.

[Prior Art] Various research and development efforts have been made to improve the fuel economy of internal combustion engines. It is generally known that increasing the compression ratio is an effective way to improve fuel economy. However, when the compression ratio of an engine is increased, knocking becomes severe in the high load range, especially in the high load range of low and medium speeds. In order to suppress this knocking, the ignition advance must be retarded, which leads to a decrease in shaft torque and a deterioration in drivability. In the end, the current situation is that increasing the compression ratio is restricted due to the knocking problem.

On the other hand, knotting occurs when unburned gas in a high-temperature part of the combustion chamber away from the ignition plug is compressed by the high temperature and rapid flame expansion around the ignition plug, causing it to spontaneously ignite before the flame arrives. It is well known that this is caused by The first high-temperature parts include the exhaust valve section, valve seat section, and their vicinity, which are constantly exposed to high-temperature exhaust gas.
If the temperature of these parts can be effectively reduced, the occurrence of knocking will be significantly suppressed.

By the way, conventional exhaust valve cooling is performed partly through the valve seat and partly through the valve guide. Therefore, cooling the valve seat contributes not only to cooling the valve seat itself and the combustion chamber wall temperature in the vicinity thereof, but also to cooling the exhaust valve. and,
Conventionally, this cooling of the valve seat is accomplished by forming an annular cooling water passage around the valve seat and connecting it to the water jacket in the cylinder head, as disclosed in the Japan Institute of Invention and Innovation Technical Report, Publication No. 79-3062. A cooling water supply hole and a cooling water discharge hole are formed between the annular cooling water passage and a part of the main flow of the cooling water flowing in the water jacket is guided to the annular cooling water passage through the cooling water supply hole. The cooling water was then allowed to flow through the cooling water discharge hole into the other water jacket. However, in the cylinder head of the internal combustion engine described in the above-mentioned Japan Institute of Invention and Innovation Technical Report, Publication No. 79-3062, the cooling water supply hole to the annular cooling water passage and the cooling water discharge hole from it are as follows:
They were at the same height.

On the other hand, although an annular cooling water passage is not formed around the valve seat, the water jacket side surface of the upper wall of the combustion chamber receives the flow flowing from the cylinder block to the cylinder head, and cools the water in the high temperature part of the upper wall of the combustion chamber. The technology to efficiently cool the upper wall of the combustion chamber by directing flow to the jacket side surface was developed in 1972.
This is shown in Publication No.-50137. However, this only cools the upper wall of the combustion chamber;
It is not applied to a cylinder head having an annular cooling water passage around the valve seat, and does not teach anything about introducing flow into the annular cooling water passage.

[Problems to be solved by the invention] In the conventional cooling structure having an annular cooling water passage around the valve seat, the direction of the flow of cooling water in the water jacket is almost perpendicular to the cooling water supply hole. The water flowing through the water jacket has difficulty flowing into the cooling water supply hole, and the annular cooling water passage around the valve seat has greater flow resistance than the water jacket, so a sufficient amount of cooling water However, even if an annular cooling water passage is provided, there is a problem in that the valve seat cannot be effectively cooled.

In addition, since the cooling water supply hole to the annular cooling water passage and the cooling water outlet hole from the annular cooling water passage were located at the same height, the cooling water heated in the annular cooling water passage was transferred to the inclined annular cooling water passage. Another problem was that the cooling water would tend to rise to the highest point in the tank by convection, making it difficult for the cooling water to flow out of the drain holes, potentially creating heat spots.

Furthermore, even with the technology disclosed in Japanese Utility Model Application Publication No. 52-50137, the upper wall of the combustion chamber near the nozzle is only effectively cooled, and the flow in the annular cooling water passage around the valve seat cannot be improved. was not connected. This is because in Utility Model Application Publication No. 52-50137, an annular cooling water passage is not provided around the valve seat, so there is no purpose of improving the flow.
Therefore, the structure was not designed for that purpose.

In view of the above points, the present invention provides an exhaust valve, an exhaust port valve seat,
In addition, in order to lower the wall temperature of the combustion chamber near the valve seat, ensure a sufficient amount of cooling water in the cooling water passage around the valve seat, and ensure a smooth flow of cooling water in the cooling water passage around the valve seat. The ultimate aim is to reduce the temperature in the high-temperature part of the combustion chamber to suppress the occurrence of knocking, improve fuel efficiency, increase torque, and improve drivability.

[Means for Solving the Problems] To achieve the above object, the cylinder head cooling device for an internal combustion engine according to the present invention is applicable to an engine having a plurality of cylinders in which the main flow of cooling water flows in the longitudinal direction of the cylinder head. Both the valve and the upper wall of the combustion chamber around the valve are arranged so as to be inclined from the horizontal, and a cooling water passage that directly contacts the valve seat is formed around the valve seat on the upper wall of the combustion chamber and is inclined from the horizontal. Openings communicating with the water jacket in the cylinder head through which the main flow of the cooling water flows are provided at the lower and upper ends of the water passage, and the water jacket in the cylinder head and the cylinder block are provided near the lower opening of the openings. A water deflector nozzle is provided in a communication hole with the inner water jacket, and the deflector nozzle is configured such that the cooling water coming out from the nozzle is directed toward the lower opening of the cooling water passage. It consists of a cylinder head cooling system for an internal combustion engine, which is located opposite the lower opening.

[Function] In the cylinder head cooling device for an internal combustion engine according to the present invention, a cooling water passage is provided around the valve seat, and the lower opening of the cooling water passage and the nozzle of the deflector are provided facing each other. Therefore, the cooling water from the water jacket in the cylinder block that has not yet risen in temperature from the deflector nozzle is efficiently taken into the cooling water passage.
A sufficient flow rate of cooling water in the cooling water passage is ensured, and the dynamic pressure biases the cooling water in the cooling water passage to flow from the lower opening to the upper opening, thereby achieving cooling. Smooth the flow of cooling water in the water passage. This flow intake effect is not found in Japanese Utility Model Application No. 52-50137.

In addition, since openings are provided at the lower and upper ends of the inclined cooling water passage around the valve seat, the temperature of the cooling water introduced into the cooling water passage from the bottom increases when cooling the valve seat. When the cooling water tries to move upward due to convection, it will flow toward the upper opening, and the rising cooling water due to convection will cause the cooling water to flow from the lower opening to the upper opening. This acts in the direction of increasing the flow of water, making the flow in the cooling water passage even smoother.
This biasing of the flow by convection is not found in the Japan Institute of Invention and Innovation Technical Report, Publication No. 79-3062.

[Embodiments] Hereinafter, preferred embodiments of the cylinder head cooling device of the present invention will be described with reference to the drawings.

FIG. 1 shows a cross-sectional view of the device according to the present invention. In the figure, a valve seat 3 whose outer circumferential surface is coated with a sealing material is attached to the exhaust port 2 of the cylinder head 1 in a fluid-tight manner. An exhaust valve 4 is provided on this valve seat 3 so that it can be seated and moved away from the valve seat 3. exhaust valve 4
The lower surface of the engine, the valve seat 3, and the upper wall of the combustion chamber around the valve seat are inclined from the horizontal and are arranged obliquely. The exhaust valve 4 is slidably supported by a valve guide 5, is always biased diagonally upward by a valve spring 6, and is driven by a cam 7 via a rocker arm 8 so as to be stroked. . A water jacket 9 is formed in the cylinder head 1 around the exhaust port 2, and the water jacket 9 formed in the portion between the exhaust passage and the gasket 10 has a water jacket 9 formed in the cylinder block 11. The cooling water from the water jacket 12 is squeezed and supplied when passing through the connection hole 13.

On the other hand, an annular cooling water passage 14 is formed around the valve seat 3 so as to be in contact with the valve seat 3, as shown in FIG. The cooling water passage 14 is formed obliquely and is inclined from the horizontal in accordance with the inclination of the valve seat 3. A cooling water supply hole 1 is provided at the lower end of the inclined cooling water passage 14.
At the upper end of the cooling water passage 14, an opening functioning as a cooling water discharge hole 18 is formed. Therefore, cylinder head 1
The inner water jacket 9 and the cooling water passage 14 around the valve seat 3 are communicated with each other through a cooling water supply hole 15. A deflector 16 that projects upward into the water jacket 9 is attached to the communication hole 13 from the water jacket 12 in the cylinder block 11. The deflector 16 is formed of a cylindrical body whose upper end is blind, and a spout 17 that opens opposite the cooling water supply hole 15 is provided at the upper end. Further, a cooling water discharge hole 18 on the opposite side to the cooling water supply hole 15 of the annular cooling water passage 14 around the valve seat 3 communicates with a water jacket 19 located on the opposite side to the cooling water passage 14.

In the cylinder head cooling device having the above configuration, the cooling water passes through the deflector 16 from the water jacket 12 in the cylinder blower 11, and the water spouted from the nozzle 17 flows through the water jacket 9 in the cylinder head 1. This disturbs the water in the vicinity of the exhaust port 2, increasing the cooling effect in the vicinity of the exhaust port 2, and much of the cooling water spouted out in a directional manner flows into the cooling water supply hole 1.
5 to ensure that a sufficient amount of water flows into the annular cooling water passage 14 around the valve seat 3, and to flow from the cooling water supply hole 15 toward the cooling water discharge hole 18 due to dynamic pressure. After being heated and flowing smoothly and sufficiently cooling the valve seat 3, the water jacket 1 is discharged from the cooling water discharge hole 18.
It flows out to 9. At this time, the cooling water whose temperature is raised while flowing in the cooling water passage 14 tends to flow upward due to convection.
The flow in the cooling water supply hole 15 flows more smoothly from the cooling water supply hole 15 toward the cooling water discharge hole 18 under the influence of convection. The cooling water, which has risen in temperature by cooling the cylinder head 1, reaches the radiator section, where it is cooled, and then circulates back to the cylinder block 11. After that, repeat the above.

[Effect of the invention] Therefore, when using the cylinder head cooling device for an internal combustion engine of the present invention, a deflector is provided,
Since the cooling water from the cylinder block is made to flow into the cooling water passage around the valve seat, a sufficient amount of cooling water can be reliably introduced into the cooling water passage around the valve seat. Therefore, the flow can be urged from the cooling water supply hole toward the cooling water discharge hole, and the valve seat can be cooled reliably and effectively.

In addition, a cooling water supply hole is provided at the lower end of the slanted cooling water passage, and a cooling water discharge hole is provided at the upper end of the cooling water passage, so that the flow is energized by convection to increase the temperature of the cooling water.
This can be effectively used to urge the flow from the cooling water supply hole to the cooling water discharge hole, and the flow in the cooling water passage can be made even smoother.

This makes it possible to reduce the temperature of the exhaust valve head, the valve seat attached to the exhaust port, and the combustion chamber wall in the vicinity, which were most likely to reach high temperatures in the past, and suppress the occurrence of knocking. . Therefore, it is possible to increase the compression ratio without causing knocking,
In addition to improving fuel efficiency, by advancing the ignition angle, it is possible to improve shaft torque and driveability.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the cylinder head cooling device for an internal combustion engine according to the present invention, and FIG. 2 is a bottom view of the cylinder head portion of FIG. 1. 1... Cylinder head, 2... Exhaust port, 3... Valve seat, 4... Exhaust valve, 9, 12, 19... Water jacket,
11...Cylinder block, 13...Communication hole, 1
4... Cooling water passage, 15... Cooling water supply hole (opening), 16... Deflector, 17... Spout, 1
8...Cooling water discharge hole (opening).

Claims (1)

[Scope of utility model registration request] In an engine that has a plurality of cylinders and the main flow of cooling water flows in the longitudinal direction of the cylinder head, the valve and the upper wall of the combustion chamber around the valve are both arranged so as to be inclined from the horizontal, and the upper wall of the combustion chamber is arranged around the valve seat. A cooling water passage in direct contact with the valve seat is formed inclined from the horizontal, and openings are provided at the lower and upper ends of the cooling water passage to communicate with a water jacket in the cylinder head through which the main flow of the cooling water flows;
A nozzle of a water deflector attached to a communication hole between the water jacket in the cylinder head and the water jacket in the cylinder block is provided near the lower opening of the opening, and the nozzle of the deflector is connected to the nozzle. A cylinder head cooling device for an internal combustion engine, characterized in that the cooling water passage is opposed to a lower opening so that the cooling water coming out of the cooling water passage is directed toward the lower opening.