KR950011324B1 - Cylinder head structure for an engine - Google Patents

Abstract

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Description

Cylinder Head Structure of Engine

1 is a cross-sectional front view showing the internal structure of the cylinder head of the engine in one embodiment of the present invention.

2 is a cross-sectional view taken along the line II-II of FIG.

FIG. 3 (a) is a view showing the shape of the intake port as seen from the cross section along the line A-A of FIG.

FIG. 3 (b) shows the shape of the intake port as seen from the cross-section B-B of FIG.

FIG. 3 (c) is a view showing the shape of the intake port as seen from the cross-section taken along the line C-C in FIG.

FIG. 3 (d) is a diagram showing the shape of the intake port as seen from the cross-section taken along the line 0-D of FIG.

FIG. 3 (e) is a view showing the shape of the intake port as seen from the cross-section taken along the line 0-E of FIG.

FIG. 3 (f) is a view showing the shape of the intake port as seen in the cross section taken along the line 0-F of FIG.

FIG. 3 (g) is a view showing the shape of the intake port as seen in the cross section taken along the line 0-G of FIG.

FIG. 3 (h) is a view showing the shape of the intake port as seen in the cross section taken along the line 0-H in FIG.

FIG. 3 (i) is a view showing the shape of the intake port as seen in the cross section taken along the line 0-I of FIG.

* Explanation of symbols for main parts of the drawings

10: cylinder head 18: valve guide portion

20: first vortex pot 22: second vortex pot

The present invention relates to a cylinder head structure of an engine having a spiral intake port.

In the conventional cylinder head, there are some intake ports leading to the combustion chamber in a spiral shape (for example, see Japanese Patent Application Laid-Open No. 63-22339). According to this structure, a swirl is formed in the intake air passing through the intake port, and the mixing of the fuel and the air is enhanced by the formation of the swirl.

In the above structure, it is confirmed that the opening area of the vortex portion in the intake port may be increased in order to increase the filling efficiency of the intake air into the combustion chamber of the engine, that is, to increase the force for pushing the intake air into the combustion chamber below. It is becoming. In the case of expanding such an opening area, there is a limit to expanding the intake port area outward in the radial direction in view of the shape of the cylinder head. Therefore, it is conceivable to enlarge this intake port in the radially inward direction. However, the intake port has a valve guide portion for mounting an intake valve therein, and it is not necessary to ensure a certain thickness of the valve guide portion. Therefore, it is difficult to simply enlarge the intake port inward. Moreover, when this intake port is expanded inward in the radial direction, the intake air easily escapes in the radial direction by that amount, and there is also a disadvantage in that the vortex forming force of the intake air by this intake port is weakened.

In view of such circumstances, an object of the present invention is to provide a cylinder head structure of an engine that can increase the opening area of an intake port and increase the filling efficiency of intake air without causing inconvenience.

In the cylinder head structure of the engine which has the same-shaped valve guide part in which the intake valve is attached, and the intake port of the vortex which reached the combustion chamber of the engine was formed, the intake port surrounds the vortex shape which encloses the said valve guide part. And a first vortex port formed to lower the upper surface as the end is closer to the terminal portion, and a second vortex port formed at the lower end of the valve guide portion and formed at the lower end as the closer to the terminal portion. It is equipped with this, and the position of the terminal part of a 1st vortex port and a 2nd vortex port is matched.

Here, it is preferable that the top heights of the first vortex port and the second vortex port are such that the top height of the second vortex port is equal to or less than the top height of the first vortex port in the entire region of these vortex ports.

According to the above structure, in addition to the first vortex port that surrounds the valve guide portion, since a second vortex port is formed therein, the downward opening area of the entire vortex port is increased accordingly, and the intake air is pushed downward. Strength increases In addition, since the second vortex port is formed at the lower end of the valve guide portion, the thickness of the valve guide portion can sufficiently ensure dimensions such as a press-fit margin of the valve. Moreover, since the position of the terminal part of both vortex ports is coincident, the downward pushing force by both ports is not disperse | distributed.

In this structure, the force for forming the vortex in the intake air is almost determined by the shape of the first vortex port located radially outward. That is, when the upper surface position of the second vortex port is higher than the upper surface position of the first vortex port, the intake air flowing through the first vortex port easily escapes into the inner second vortex port, and the vortex forming force is weak. Easy to lose Therefore, as described above, in the entire region of the two vortex ports, the upper surface height of the second vortex port is set to be equal to or less than the upper surface height of the first vortex port, and thus higher vortex forming force can be ensured.

An embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 10 denotes a cylinder head mounted on the upper surface of the cylinder block 12. As shown in FIG. The center port 14 which opens downward is formed in the center lower part of this cylinder head 10, This center port 14 opposes the combustion chamber formed in the said cylinder block 12. As shown in FIG. Above the center port 14, a cylindrical valve guide portion 18 extending in the vertical direction is formed, and the intake valve (not shown) is pushed into the through hole 16. In addition, the valve seat 15 is formed at the edge of the lower end of the center port 14.

As shown in Fig. 2, the cylinder head 10 is provided with a first vortex port 20 that reaches the center port 14 from its side surface, and the first vortex port 20 is formed. ), As shown in Figs. 3 (a) to 3 (i), is formed in a spiral shape in which the upper surface position is lowered toward the terminal portion.

Moreover, as a characteristic of this cylinder head 10, as shown in FIG. 1 and FIG. 2 as a mesh area | region, the inner part of the said 1st vortex port 20 (namely, the valve guide part 18). The second vortex port 22 is formed by cutting off the lower end of the. Similar to the first vortex port 20, the vortex port 22 is formed in a vortex shape in which the upper surface position is lowered toward the end portion thereof.

As shown in the third (b) and the third (c) degrees, the second vortex port 22 has an upper surface height lower than that of the first vortex port 20 at the start end position thereof. It has a position and maintains a constant top height position up to the point where the first vortex port 20 and the top height position become equal as shown in the drawing (g), but from this point to the end In this region, the upper surface height position gradually decreases while securing an upper surface height position equivalent to that of the first vortex port 20. That is, as shown in the same figure (i), the terminal positions of both vortex ports 20 and 22 are set to the same position.

The position of the upper surface height of the second vortex port 22 at the start end position is the pressure of the intake valve of the intake valve in the valve guide portion 18 (that is, the valve guide portion 18). It is set so low that the dimension of the up-down direction can be sufficiently secured.

Next, the operation of this cylinder head 10 will be described.

The intake air introduced into the first vortex port 20 through the intake passage not shown in the drawing passes through the first vortex port 20 and reaches the center port 14 in the combustion chamber in the cylinder block 12. In this case, a vortex is formed in the intake air passing through the first vortex port 20, and the mixing of air and fuel is enhanced by the formation of the vortex.

Since the second vortex port 22 is formed inside the first vortex port 20, the downward opening areas of all the vortex ports 20 and 22 are enlarged, so that these vortex ports are formed. The force for pushing the intake air downward by the ports 20 and 22 is higher than that in the conventional structure, whereby the charging efficiency of the intake air is increased.

Here, the top height position of the second vortex port 22 is always equal to the height position of the first vortex port 20, that is, the area of the first vortex port 20 is simply radially inward. In the enlarged structure, sufficient inlet pressure of the intake valve cannot be ensured in the valve guide portion 18, and the intake air passing through the first vortex port 20 easily escapes in the radial direction. Therefore, the vortex forming power is weakened.

On the other hand, in the structure of the present embodiment, since the second vortex port 22 is formed only at the lower end of the valve guide portion 18, the pressurized margin of the valve guide portion 18 can be sufficiently secured, and thus the valve The function of the guide part 18 is not impaired. Moreover, in the area | region shown to FIG. 3 (b)-3 (f), the position of the upper surface height of the 2nd vortex port 22 is lower than the position of the upper surface height of the 1st vortex port 20. FIG. As a result, sufficient vortex forming force can be ensured in the first vortex port 20 above the upper surface of the second vortex port 22 as in the prior art. That is, in this structure, while effectively using the space in which the lower end part of the valve | bulb drive part 18 is located, the opening area is enlarged without inconvenience.

In particular, in this embodiment, as shown in FIGS. 3 (b) to 3 (i), the second vortex port 22 is formed in the entire region of both vortex ports 20 to 22. Since the upper surface height of is less than or equal to that of the first vortex port 20, a large vortex forming force is secured at all times.

In the above structure, since the end positions of both vortex ports 20 and 22 are aligned, the pushing force of the intake air by both vortex ports 20 and 22 is not dispersed.

In addition, in this invention, the time unit value of a 2nd vortex port does not have a problem especially, The terminal position should just match with the end position of a 1st vortex port.

In addition, in the above embodiment, the first vortex port 20 and the second vortex port 22 communicate with each other over the entire region, but the present invention is not limited thereto, and these vortex ports 20 The same effect as described above can be obtained even when the structures 22 and 22 are independent of each other, that is, the structure in which both the vortex ports 20 and 22 are partitioned by a wall.

As described above, the present invention increases the downward opening area of the entire vortex port by forming the second vortex port in addition to the vortex-shaped first vortex port and using the valve guide portion located in the radially inner side thereof. In addition, since the end positions of both vortex ports coincide, the increase in the opening area effectively increases the force for pushing the intake air downward, thereby increasing the filling efficiency of the intake air into the combustion chamber.

In addition, since the second vortex port is formed at the lower end of the valve guide portion, the above effects can be obtained without harming the shape of the valve guide portion, and the vortex forming force of the first vortex port is also maintained sufficiently high. Can be.

In particular, by making the height of the upper surface of the second vortex pot equal to or less than the height of the surface of the first vortex port in the entire region of both vortex ports, higher vortex forming force can be ensured.

Claims (1)

In a cylinder head structure of an engine having a cylindrical valve guide portion to which an intake valve is mounted, and having a spiral intake port leading to the combustion chamber of the engine, the intake port has a swirl shape surrounding the valve guide portion. A first vortex port formed to lower the upper surface position closer to the terminal portion, and a second vortex port formed at the lower end of the valve guide portion, and formed to lower the upper surface position closer to the terminal portion, The termination positions of these first vortex ports and the second vortex port are matched, and in the whole region of the first vortex port and the second vortex port, the upper surface height of the second vortex port is the first vortex port. An engine cylinder head structure, characterized in that the height of the upper surface of the port or less.