JPH0517367Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a rotary intake/exhaust valve device for an engine, and in particular, it is capable of preventing gas leakage to the intake/exhaust port and a decrease in combustion efficiency due to this, and The present invention relates to a rotary intake/exhaust valve device for an engine that can prevent the occurrence of carbon stains on the exhaust valve.

<Prior Art> In order to increase the output of an engine, it is necessary to increase the rotational speed or perform high supercharging. Furthermore, in order to reduce the fuel consumption rate, it is necessary to increase the compression ratio. However, with poppet-type intake and exhaust valves, increasing the rotational speed is limited by the inertia of the valve mechanism and gas velocity, and increasing the compression ratio and boost pressure can cause premature ignition or knocking due to overheating of the exhaust valve. There is a limit to Although the problem of fuel leakage can be solved by using high-octane gasoline, such fuel is expensive, so poppet-type intake and exhaust valves seem to have reached a dead end in improving performance. Rotary intake/exhaust valves are superior to poppet-type intake/exhaust valves in the following points, and are attracting attention as a means of overcoming the limits of performance improvement of poppet-type intake/exhaust valves.

In other words, compared to poppet-type intake and exhaust valves, rotary intake and exhaust valves can have a larger opening area, so they have lower volumetric efficiency for the same piston speed.
The average effective pressure can be increased, and the limit to which the average effective pressure decreases as the rotational speed increases is extended, and as a result, the little horsepower can be increased.

Even at high speeds, there is no risk of valve spring surging or excessive cam pressure, and operation is reliable.

Since there is no exhaust valve that becomes a hot spot, and the shape of the combustion chamber can be improved, the compression ratio and boost pressure can be increased, and therefore the fuel consumption rate and limited output can be increased.

Unlike poppet valves, there is no valve gap, so operation is quiet.

By the way, there are two types of rotary intake and exhaust valves for engines: those in which the rotary valve rotates around an axis parallel to the center of the cylinder, and those in which the rotary valve rotates around an axis perpendicular to the center of the cylinder. The shape is formed into a rotating body shape such as a cylindrical shape, a truncated cone shape, a spherical shape, etc. centered on the rotation axis.

In these conventional rotary intake/exhaust valves, in order to prevent gas leakage between the intake/exhaust valve and the valve chamber that houses it, the gap between the intake/exhaust valve and the valve chamber is made as small as possible. At the same time, it is configured to form a lubricating oil film in the gap.

<Problems to be solved by the invention> However, with such conventional rotary intake/exhaust valves, gas leaks from the combustion chamber into the valve rotation gap between the intake/exhaust valve and the valve chamber, and output decreases due to this. However, due to this gas leakage, there is a problem in that carbon sticks are likely to occur due to carbon entering the valve rotation gap between the intake/exhaust valve and the valve chamber, and so far it has not been put into practical use.

The present invention has been developed in consideration of the above circumstances, and is a rotary intake/exhaust system for an engine in which a valve chamber is formed in the middle of the intake/exhaust port of the engine, and a rotary valve is rotatably fitted in the valve chamber. To provide a rotary intake and exhaust valve device for an engine, which can prevent gas leakage to an intake/exhaust port and a decrease in combustion efficiency due to this, as well as prevent carbon stains from occurring in the intake/exhaust valve. The purpose is to

<Means for solving the problems> In order to achieve the above object, in the rotary intake and exhaust valve device for an engine according to the present invention, high pressure gas in the combustion chamber is transferred from the intake and exhaust port to the valve chamber and the rotary valve. A pair of elastic seal rings that prevent leakage into the valve rotation gap between the valves are inserted into the part surrounding the intake and exhaust ports in the valve rotation gap, and the base end of each elastic seal ring is airtightly attached to the inner peripheral surface of the valve chamber. At the same time, its tip is brought into airtight contact with the rotary valve, and the high-pressure fluid introduction passage and outlet passage are communicated between the two elastic seal rings in the valve rotation gap, and the high-pressure fluid supply device attached to the engine is connected to the high-pressure fluid supply passage. The present invention is characterized in that the fluid is configured to pass through the valve rotation gap from the inlet passage and flow out from the outlet passage.

[Effect]

The valve rotation gap between the valve chamber and the rotary valve is sealed at the part surrounding the intake/exhaust port by an elastic seal ring inserted in the part surrounding the intake/exhaust port in the valve rotation gap, and the high-pressure fluid supply device The high-pressure fluid introduced into the valve rotation gap through the introduction path further improves the sealing performance. As a result, it is possible to prevent gas leakage from the combustion chamber to the valve rotation gap, prevent a decrease in output due to such gas leakage, and prevent carbon from entering the valve rotation gap due to gas leakage from the combustion chamber. It is possible to prevent the occurrence of carbon stuck, where carbon is deposited in the valve rotation gap and the rotary valve and the circumferential surface of the valve chamber stick together.

Furthermore, the rotary valve can be cooled by discharging high-pressure fluid from the valve rotation gap through the lead-out passage. Furthermore, the high-pressure fluid fills the valve rotation gap around the rotary valve, forming an air bearing that supports the rotary valve in a floating state, thereby smoothing the rotation of the rotary valve.

Although the inlet passage or the outlet passage is not particularly limited, one or both of them can be formed within the valve stem of the rotary valve.

In carrying out the present invention, there is no particular limitation on the location where the inlet passage or outlet passage is formed; for example, they may be formed within the wall of the engine such as the cylinder head, or inside the intake and exhaust valves and their valve shafts. It is possible to form it so that it passes through.

<Example> Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 is a longitudinal cross-sectional view of a rotary intake and exhaust valve for an engine according to an embodiment of the present invention, FIG. 2 is a cross-sectional plan view of a cylinder head of the engine, and FIG. 3 is an elastic seal ring thereof. FIG.

An intake port 3 and an exhaust port 4 are formed in the cylinder head 2 of this engine 1, and a spherical intake valve chamber 5 or exhaust valve chamber 6 is formed in the middle of these intake ports 3 and exhaust port 4, respectively. There is. The cap 2a surrounding the port portions 3a, 4a of the intake port 3 and the exhaust port 4 on the combustion chamber 11 side is made of ceramic having excellent heat resistance and pressure resistance.

A spherical ceramic intake valve 7 or exhaust valve 8 is rotatably fitted into the intake valve chamber 5 or the exhaust valve chamber 6, respectively. The intake valve 7 is an intake valve drive shaft 9 that rotates at 1/2 the rotation speed relative to a crankshaft (not shown) of the engine 1.
The exhaust valve 8 is connected by a square shaft fit to an exhaust valve drive shaft 10 which rotates in time at 1/2 the rotation speed of the crankshaft.

The airtight structure of the gap between the intake valve chamber 5 and the intake valve 7, which is important in the present invention, and the airtight structure of the gap between the exhaust valve chamber 6 and the exhaust valve 8 are constructed in the same way.
Here, the former will be explained, and the latter will be omitted to avoid duplication.

The valve rotation gap 12 between the intake valve chamber 5 and the intake valve 7 in the intake valve chamber 5 includes a portion surrounding the intake port portion 3a on the combustion chamber 11 side and a portion surrounding the intake port portion 3b on the inlet side. Elastic seal ring 1
3 and 14 are inserted. Each elastic seal ring 1
The base end portions 13a, 14a of No. 3, 14 are connected to respective circumferential grooves 15, 16 formed on the inner circumferential surface of the intake valve chamber 5, respectively.
The tips 13b and 14b of each elastic seal ring 13 and 14 are connected to the intake port portion 3a on the combustion chamber 11 side or the intake port on the inlet side, respectively. It extends from the port portion 3b to the center side of the valve rotation gap 12 and is brought into airtight contact with the intake valve 7. Note that these elastic seal rings 13 and 14 are required to have heat resistance and pressure resistance to the extent that they can withstand combustion within the combustion chamber 11.

The intake valve drive shaft 9 is located near the intake valve chamber 5,
It is rotatably supported by the cylinder head 2 via an elastic seal ring 17 made of, for example, an O-ring. The surfaces of the portions 9a and 9b of the intake valve drive shaft 9 that come into sliding contact with the elastic seal ring 17 are sintered with ceramics as necessary to increase wear resistance.

The terminal end of an introduction path 18 connected to a high-pressure air supply device (not shown) is opened in the upper half of the valve rotation gap 12, and the high-pressure air is discharged from the lower half of the valve rotation gap 12. The starting end of the lead-out path 19 is open. The above high-pressure air supply device supplies clean high-pressure air from which foreign matter such as dust has been removed to the introduction path 1.
8 to the valve rotation gap 12.

In FIG. 2, 4a indicates an exhaust port portion on the combustion chamber 11 side, and 4b indicates an exhaust port portion on the exit side.

According to the rotary intake and exhaust valve for the engine configured in this way, the elastic seal rings 13 and 14 in the intake valve chamber 5 have their base ends 13a and 14a airtightly attached to the inner circumferential surface of the intake valve chamber 5. While being fixed, the tip portions 13b and 14b are connected to the port portion 3 on the combustion chamber 11 side.
It extends from the port portion 3b on the inlet side to the center of the valve rotation gap 12 and is brought into airtight contact with the intake valve 7. Therefore, the elastic seal rings 13, 14
The tip portions 13b, 14b are brought into close contact with the intake valve 7 by their elastic restoring force.

Also, both elastic seal rings 1 of the valve rotation gap 12
3 and 14, clean high-pressure air from which foreign matter such as dust has been removed is supplied from a high-pressure air supply device through an inlet path 18, and the high-pressure air is discharged through an outlet path 19. Therefore, the internal pressure of the portion of the valve rotation gap 12 partitioned by both the elastic seal rings 13 and 14 is maintained at a high pressure higher than a predetermined pressure.

As a result, the high-pressure air filling this area is transferred to the tips 13b, 14 of both elastic seal rings 13, 14.
b is pressed more forcefully against the intake valve 7 to improve sealing performance. Therefore, it is possible to prevent gas leakage from the combustion chamber 11 to the valve rotation gap 12 and the inflow of carbon into the valve rotation gap 12 due to such gas leakage.
This makes it possible to prevent the occurrence of carbon stains due to carbon buildup.

Furthermore, both elastic seal rings 1 of the valve rotation gap 12
Since the high-pressure air in the portion divided by 3 and 14 functions as an air bearing that supports the intake valve 7 in a floating state, rotation of the intake valve 7 is facilitated.

In addition, the heat conducted or radiated from the intake valve 7 to this high-pressure air is carried to the outside together with the high-pressure air flowing out via the outlet path 19, so that the intake valve 7 is cooled.

FIG. 4 is a longitudinal cross-sectional view of another embodiment of the present invention. In this embodiment, the introduction passage 18 is formed to pass inside the intake valve 7 and the intake valve drive shaft 9, and the intake valve 7 is Each terminal end of the introduction passage 18 branched into a cross shape along the valve passage 20 inside the intake air source 7 is opened to the surface of the air intake source 7 . Further, the lead-out passage 19 is opened on the circumferential surface of the drive shaft insertion hole 21 that communicates with the valve rotation gap 12 . The starting end of the outlet path 19 is opened at the inner peripheral surface of the portion of the drive shaft insertion hole 21 through which the drive shaft 9 is inserted, which communicates with the valve rotation gap 12 .

Other configurations, operations, and effects are similar to those of the above-described embodiment, so their description will be omitted to avoid duplication.

FIG. 5 is a longitudinal cross-sectional view of another embodiment of the present invention, and in this embodiment, the terminal ends of the outlet passage 19 branched within the intake valve 7 are spaced apart in the axial direction of the circumferential surface of the intake valve 7. It is opened in two places.

The other configuration of this embodiment is the same as that of the previous example except that the inlet path 18 and the outlet path 19 are reversed, and the operation and effect are essentially the same, so a description thereof will be given below. is omitted to avoid duplication.

In each of the above embodiments, the intake and exhaust valves 5 and 6 are formed in a spherical shape, but the shape of the intake and exhaust valves 5 and 6 is not limited to this. It is possible to apply the present invention even when the body shape is formed.

Furthermore, the inlet passage 18 and the outlet passage 19 have a mutually complementary relationship in order to circulate high-pressure air to the valve rotation gap 12, and their arrangement can be reversed. For example, in the embodiment shown in FIG. 4, it is possible to open the terminal end of the introduction passage 18 on the circumferential surface of the drive shaft insertion hole 21 and form the outlet passage 19 inside the intake valve 7 and the drive shaft 9. Or, in the embodiment shown in FIG. 5, the introduction passage 18 is formed so as to pass through the intake valve 7 and the drive shaft 9, and its terminal ends are located at two points apart in the axial direction of the circumferential surface of the intake valve 7. It is possible to open it with.

<Effects of the invention> As described above, according to the invention, the valve rotation gap formed between the rotary valve and the valve chamber that accommodates the rotary valve is closed on the combustion chamber side by a pair of elastic seal rings. High-pressure air is made to flow into the valve rotation gap section that is blocked from the port section and the port section on the inlet side and divided by both elastic seal rings, so the pressure of this high-pressure air causes both elastic seals to suck and exhaust more strongly. It is pressed against the circumferential surface of the valve, improving its sealing performance. As a result, gas leakage from the combustion chamber to the valve rotation gap and the accompanying carbon intrusion into the valve rotation gap are prevented, resulting in a reduction in output due to gas leakage, carbon accumulation in the valve rotation gap, and the resulting carbon stake. This means that such occurrences can be prevented. Furthermore, since high-pressure air is made to flow through the valve rotation gap defined by both elastic seal rings, the intake and exhaust valves are supported in a floating state by the internal pressure, and rotation of the intake and exhaust valves becomes smooth. Furthermore, since high-pressure air is discharged to the outside through the outlet path into the valve rotation gap defined by both elastic seal rings, the heat conducted or radiated from the intake valve to this high-pressure air is released to the outside. The intake and exhaust valves can be cooled.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a rotary intake and exhaust valve for an engine according to an embodiment of the present invention, FIG. 2 is a cross-sectional plan view of the cylinder head of the engine, and FIG. 3 is an enlarged sectional view of the elastic seal ring. , FIG. 4 is a longitudinal cross-sectional view of another embodiment of the present invention, and FIG. 5 is a longitudinal cross-sectional view of another embodiment of the present invention. 1...Engine, 3...Intake port, 3a...
Intake port part on the combustion chamber side, 3b...Intake port part on the inlet side, 4...Exhaust port, 4a...Exhaust port part on the combustion chamber side, 4b...Exhaust port part on the inlet side, 5...Intake valve Chamber, 6...Exhaust valve chamber, 7
... Intake valve, 8 ... Exhaust valve, 11 ... Combustion chamber, 1
2... Valve rotation gap, 13... Elastic seal ring,
13a...base end of elastic seal ring, 13b...
...Distal end of the elastic seal ring, 14...Elastic seal ring, 14a...Proximal end of the elastic seal ring, 14b...Distal end of the elastic seal ring, 18
...Introduction path, 19...Output path.

Claims (1)

[Claims for Utility Model Registration] 1 Valve chambers 5 and 6 are formed in the middle of the intake and exhaust ports 3 and 4 of the engine 1, and rotary valves 7 and 8 are formed in the valve chambers 5 and 6.
In the rotary intake/exhaust valve of the engine, which is rotatably fitted inside the
A pair of elastic seal rings 13 and 14 are attached to the intake and exhaust ports 3 and 4 in the valve rotation gap 12 to prevent leakage from the valve chambers 5 and 6 to the valve rotation gap 12 between the valve chambers 5 and 6 and the rotary valves 7 and 8. The proximal end portion 13a of each elastic seal ring 13, 14 is inserted into the surrounding portion.
14a is hermetically fixed to the inner peripheral surfaces of the valve chambers 5 and 6, and its tips 13b and 14b are hermetically contacted to the rotary valves 7 and 8, and high-pressure fluid is supplied to the valve rotation gap 12 between both elastic seal rings. The introduction passage 18 and the outlet passage 19 are communicated with each other, and the high pressure fluid of the high pressure fluid supply device attached to the engine 1 is configured to pass through the valve rotation gap 12 from the introduction passage 18 and flow out from the outlet passage 19. The engine features rotary intake and exhaust valves. 2. The rotary intake and exhaust valve for an engine according to claim 1, wherein the inlet passage 18 or the outlet passage 19 passes through the valve shafts 9, 10 of the rotary valves 7, 8.