JPH0511286Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to rotary intake and exhaust valves for engines, and is a technology for improving intake and exhaust efficiency.

[Prior Art] A conventional rotary intake and exhaust valve for an engine is shown in FIG. 7 or 9. All of these have the following basic structure similar to the present invention. That is, a rotary valve 9 is interposed between the intake and exhaust ports 7 and 8 of the engine 1, and the rotary valve 9 has a valve passage 13 formed in a valve shaft 12.

Prior art 1 Conventional technology 1 shown in Fig. 7 has the basic structure described above, with intake and exhaust ports 7 and 8 formed in a vertical straight line from the upper side of the cylinder head toward the combustion chamber, and a rotary valve 9 disposed in the middle. The valve passages 13 are arranged in a cross-shaped manner, and each valve passage 13 is provided in the form of a hole in the radial direction of the valve shaft 12.

Prior art 2 Conventional technology 2 shown in FIG.
In the above basic structure, the intake and exhaust ports 7 and 8 are bent into an elbow shape from the side of the cylinder head toward the combustion chamber, and a rotary valve 9 is installed at the bent part. The valve passages 13 are formed in a groove shape along the circumferential direction of the valve shaft 12, and the bottom surface 13a of each valve passage 13 extends from the axis of the valve shaft 12 along its length. It is formed into a convex curved surface that is equidistant.

[Problem to be solved by the invention] In the prior art 1 shown in FIG. 7, as the valve shaft 12 rotates, the intake port 7 and the exhaust port 8 are opened and closed at two locations, the inlet and the outlet, of the valve passage 13. , there is the following problem. This will be explained based on FIG.

Figure 8 is a partial view of Figure 7 showing the intake valve side.
FIG. 8a shows the initial stage of valve opening, and FIG. 8b shows the final stage of valve opening. As shown in this figure, although the valve passage 13 itself has a linear shape with low ventilation resistance, at the beginning and end of the valve opening, the intake A
is subjected to throttling resistance, which reduces intake efficiency. Exhaust efficiency also decreases for the same reason.

Furthermore, in prior art 1, the intake and exhaust ports 7 and 8
Since the cylinder head is formed vertically in a straight line from the top of the cylinder head toward the combustion chamber, it is necessary to install intake and exhaust pipes (not shown) that connect to the intake and exhaust ports 7 and 8 on the top of the cylinder head. , the overall height of the engine increases.

In prior art 2 shown in FIG.
When flowing into the air, the air is suddenly bent at the tip end surface 13b of the valve passage 13, which has a small radius of curvature, so the ventilation resistance of the valve passage 13 itself is large and the intake efficiency is low. For the same reason, the exhaust efficiency is also low.

The problem of this invention is to reduce the ventilation resistance at the entrance and exit of the valve passage at the beginning and end of opening, while keeping the ventilation resistance of each valve passage itself small in rotary intake and exhaust valves for engines. By doing so, it is an object of the present invention to provide an engine that can sufficiently increase the intake and exhaust efficiency and at the same time reduce the overall height of the engine.

[Means for Solving the Problems] As shown in FIG. 1
The rotary intake/exhaust valve for an engine formed with the structure No. 3 is characterized by the following features.

That is, the intake and exhaust ports 7 and 8 are bent into an elbow shape from the side of the cylinder head 3 toward the combustion chamber 5, and the rotary valves 9 are positioned in the bent portion in a cross-shaped manner. The valve stem 1
2, and the bottom surface of each valve passage 13 is formed in a groove shape along the circumferential direction of the valve passage 2, and the bottom surface of each valve passage 13 is formed so that the bottom surface 13a of each groove-shaped valve passage 13 is closest to the axis of the valve shaft 12 at the central part in the length direction. 13a is formed into one continuous concave curved surface along its length.

[Operation] The rotary valve 9 rotates in the direction of arrow R to open and close the intake passage, as shown in FIGS. 4a, b, and c. At the beginning of the valve opening, as shown in FIG. 4a, the starting edge 13b of the groove-shaped valve passage 13 passes through the outlet 7b of the intake port 7 and then reaches the inlet 7a, where the valve passage 13 is closed. However, the valve passage 13 is fully opened at the outlet 7b. In the middle stage of valve opening, as shown in Figure 4b,
The starting edge 13b fully opens the inlet 7a, and the outlet 7b also fully opens without the starting edge 13c reaching the outlet 7b. At the end of the valve opening, as shown in FIG. 4c, the terminal edge 13c narrows the outlet 7b, but the inlet 7a is fully opened. A similar effect can be obtained on the exhaust side.

In this way, at the beginning of the valve opening, the intake port 7
The outlet 7b of the valve is fully opened, and at the end of the valve opening, the inlet 7b is fully opened.
Since a is fully opened, there is no aperture resistance here.

Further, as shown in FIG. 1, the bottom surface 13a of each valve passage 13 is formed into a single concave curved surface that continues along its length, and its radius of curvature is large, so that the intake air flows through the intake port 7. When flowing from the inlet 7a through the valve passage 13 to the outlet 7b, it is gently bent at the valve passage bottom surface 13a, which has a large radius of curvature. A similar effect can be obtained on the exhaust side. Therefore, the ventilation resistance of each valve passage 13 itself is small.

As described above, each valve passage 13 is formed in a groove shape along the circumferential direction of the valve shaft 12, and the bottom surface 13a of each groove-shaped valve passage 13 is formed in a concave curved shape with a large radius of curvature. While the ventilation resistance of each valve passage 13 itself is kept low, at the beginning and end of the valve opening, either the inlet or the outlet of the port is fully open, so the intake and exhaust only encounter throttling resistance at one point. , the intake and exhaust efficiency can be increased.

Since the intake and exhaust ports 7 and 8 are bent in an elbow shape from the side of the cylinder head 3 toward the combustion chamber 5, the intake and exhaust pipes connected to the intake and exhaust ports 7 and 8 are connected to the cylinder head 3. It can be installed on the side of the engine, reducing the overall height of the engine.

[Example] Hereinafter, an example of this invention will be described with reference to the drawings.

<<First Embodiment>> FIGS. 1 to 4 show a first embodiment.
Figure 1 is a sectional view taken along the - line in Figure 2, Figure 2 is a longitudinal sectional view of the upper part of the engine, and Figure 3 is a - line sectional view in Figure 2.
A sectional view taken along the line, FIG. 4 is a partial view of FIG. 1.

Cylinder head 3 is attached to the top of cylinder block 2.
A combustion chamber 5 is formed between the bottom surface of the cylinder head 3 and the top surface of the piston 4.

In the cylinder head 3, an intake port 7 and an exhaust port 8, which are circular in cross-section, are bent into a 90° elbow shape from the side of the cylinder head 3 toward the combustion chamber 5, respectively. These intake/exhaust ports 7, 8 are arranged with a predetermined gap left and right in the left and right direction in FIG. ), the outlet 7b of the intake port 7
The inlet 8a of the exhaust port 8 is opened to the combustion chamber 5.

Rotary valve 9 in the above intake/exhaust ports 7 and 8
is mediated. That is, the valve chamber 11, which is circular in cross section, is formed in a cross-sectional shape across both bent portions of the intake and exhaust ports 7 and 8. A valve shaft 12 is rotatably fitted into the valve chamber 11 in an airtight manner.

Valve passages 13, 13 are formed in the valve shaft 12, corresponding to the intake/exhaust ports 7, 8. Each valve passage 1
3 is formed in a groove shape along the circumferential direction of the valve shaft 12;
Bottom surfaces 13a, 1 of each groove-shaped valve passage 13, 13
The bottom surface 1 of each valve passage 13, 13 is arranged so that the center portion of the valve passage 3a is closest to the axis of the valve shaft 12 at the central portion in the longitudinal direction.
3a and 13a are formed into one continuous arcuate concave curved surface along the length direction.

Incidentally, FIGS. 4 a to 4 c show the state in which the rotary valve 9 configured as described above opens and closes the intake port 7. In the figure, arrow R indicates the rotation direction of the valve shaft 12,
Its rotation speed is reduced to 1/2 of the crankshaft rotation speed. Further, in the figure, arrow A indicates the flow of intake air.

FIGS. 5 and 6 show other embodiments, and FIGS.
A configuration different from the embodiment will be explained.

<<Second Embodiment>> FIG. 5 shows a second embodiment, and is a diagram corresponding to FIG. 3. In this embodiment, the intake/exhaust ports 7, 8
is formed into a rectangular shape in cross-sectional view, and correspondingly,
The bottom surface 13a of the valve passage 13 of the valve shaft 12 is formed into a square shape.

<<Third Embodiment>> FIG. 6 shows a third embodiment, and is a diagram corresponding to FIG. 1. In this embodiment, two valve passages 13 corresponding to the intake ports 7 are formed symmetrically with respect to the axis of the valve shaft 12. In this case, the rotation speed of the valve shaft 12 is reduced to 1/4 of the rotation speed of the crankshaft. Note that two valve passages 13 corresponding to the exhaust port 8 are also formed in the same way as on the intake side.

[Effect of the invention] Each valve passage is formed into a groove shape along the circumferential direction of the valve shaft, and the bottom surface of each groove-shaped valve passage is formed into a concave curved shape with a large radius of curvature. While keeping the ventilation resistance low, at the beginning and end of the valve opening, one of the port inlet and outlet is fully open, so the intake and exhaust only encounter throttling resistance in one place, which improves the intake and exhaust efficiency. can be increased.

Since the intake and exhaust ports are bent into an elbow shape from the side of the cylinder head toward the combustion chamber, the intake and exhaust pipes that connect to the intake and exhaust ports can be installed on the side of the cylinder head. The overall height of the engine can be lowered.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of this invention, and FIG. 1 is a cross-sectional view taken along the - line in FIG.
The figure is a vertical sectional view of the upper part of the engine, FIG. 3 is a sectional view taken along the - line in FIG. 2, FIG. 4 is a partial view of FIG. 1, FIG. FIG. 4b is a diagram showing the middle stage of valve opening, and FIG. 4c is a diagram showing the final stage of valve opening. FIG. 5 is a diagram equivalent to FIG. 3 showing the second embodiment, and FIG. 6 is a diagram equivalent to FIG. 1 showing the third embodiment. 7 and 8 show prior art 1;
The figure is a diagram equivalent to Figure 1, and Figure 8 is a partial diagram of Figure 7.
FIG. 8a is a diagram showing the initial stage of valve opening, and FIG. 8b is a diagram showing the final stage of valve opening. FIG. 9 is a longitudinal sectional front view showing Prior Art 2. 1...Engine, 3...Cylinder head, 5...
...Combustion chamber, 7...Intake port, 8...Exhaust port, 9...Rotary valve, 12...Valve shaft, 13
...Valve passage, 13a...bottom of 13.

Claims (1)

[Claims for Utility Model Registration] A rotary valve 9 is interposed between the intake and exhaust ports 7 and 8 of the engine 1, and the rotary valve 9 is a rotary intake and exhaust valve for an engine in which a valve passage 13 is formed in a valve shaft 12. In this step, the intake and exhaust ports 7 and 8 are bent into an elbow shape from the side of the cylinder head 3 toward the combustion chamber 5, and
The rotary valves 9 are disposed at the bent portions in a cross-shaped manner, and each valve passage 13 is formed in a groove shape along the circumferential direction of the valve shaft 12, and the bottom surface 13a of each groove-shaped valve passage 13 is The bottom surface 13a of each valve passage 13 is formed into a continuous concave curved surface shape along its length so that the bottom surface 13a of each valve passage 13 is closest to the axis of the valve shaft 12 at the center of the valve shaft 12. Engine rotary intake and exhaust valve.