JPH0953420A - Valve gear of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable it to realize a valve gear that has contrived an improvement in the efficiency of an internal combustion engine making up a convexly curved bulge on the underside of an exhaust valve. SOLUTION: A convexly curved bulge 16 toward the side of a combustion chamber is formed on the underside of an exhaust valve 1, and an outer surface of this valve 1 is made up into being almost streamlined form so as to make exhaust gas flow to the downstream side smoothly along a peripheral surface of the bulge 16 whenever the exhaust valve 1 is opened. Plural pieces of nearly spiral grooves 18 and a wall 20 are set up in an umbrellas part 17 of the exhaust valve 1 axisymmetrically with an axial center C2 of a stem 3 as the center in an alternate way, and a flat surface 19 is formed on top of this stem 3 and thereby the exhaust valve 1 is made so as not to be rotated at all. The exhaust valve 1 is opened and exhaust gas made smoothly flowing on an outer surface of the bulge 15 flows into the nearly spiral groove 18 installed in the umbrellas part 17, and it turns to a swirl flow, turning along a curved surface of the groove 18, and then it is smmothly and speedily discharged to the downstream of an exhaust port 5, so that any possible pumping loss is decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve device for an internal combustion engine, and more particularly to an intake valve which is provided with an exhaust valve capable of smoothly discharging exhaust gas, and which is capable of smoothly intake intake gas. The present invention also relates to a valve device for an internal combustion engine.

[0002]

2. Description of the Related Art FIG. 10 shows a cross-sectional view of the upper portion of a cylinder of a valve device for a conventional internal combustion engine. In the figure, 100 is an exhaust valve, 101 is an umbrella part thereof, 102 is a stem of the exhaust valve 100, 103 is a valve face, 105 is an exhaust port at the end, 106 is an intake valve, 107 is an intake port at the end. ing. A piston 110 is reciprocally fitted in the cylinder 109, and the cylinder 1
A cylinder head 11 is provided on the upper part of 09 through a gasket.
1 is fixed. An exhaust port 105 is formed inside the cylinder head 111.
An annular valve seat 112 is attached to the open end of the valve 5 by a method such as casting or press-fitting. When the valve is closed, the valve face 1 of the exhaust valve 100 is attached to the valve seat surface.
The outer peripheral edge of 03 closely contacts in a ring shape, and blocks the exhaust port 105 and the combustion chamber.

[0003]

In the conventional exhaust valve 100, since the lower surface 113 facing the cylinder 109 side is substantially flat, when the gas is exhausted during the exhaust stroke, as shown in FIG.
The area on the lower surface 113 side indicated by the dotted area A is a so-called dead water area where the velocity is almost 0 and the pressure is high. On the other hand, since the umbrella portion 101, which is the upper surface of the exhaust valve 100 on the downstream side of the exhaust gas, has the same shape as the umbrella portion 108 of the intake valve 106, a smooth shape is suitable for the inflow of the intake gas as the intake valve 106. However, in the region on the side of the umbrella portion 101, which is indicated by the vortex range B in FIG. 10, the exhaust gas flow is greater than that of the umbrella portion 101 because the umbrella portion 101 is excessively dug inward for the exhaust gas to flow out. Even the curved surface of 101 cannot be followed and peels off. From the above, the conventional exhaust valve 100 has a problem that the smooth outflow of exhaust gas is hindered and the efficiency of the internal combustion engine deteriorates.

The present invention has been devised in view of the above-mentioned problems of the prior art, and an object thereof is to provide an exhaust valve capable of smoothly discharging exhaust gas, An object of the present invention is to provide a valve device capable of reducing so-called pumping loss and improving the efficiency of an internal combustion engine by also including an exhaust valve capable of smoothly sucking intake gas.

[0005]

In order to solve the above problems, the present invention provides an internal combustion engine including an intake valve having a stem provided in an intake port and an exhaust valve having a stem provided in an exhaust port. In the valve device, the lower surface of the exhaust valve is formed with a bulging portion that is curved in a convex shape and has an outer surface that forms a substantially streamlined curved surface, and the umbrella portion that is the upper surface of the exhaust valve has a plurality of bulging portions. Substantially spiral groove portions and wall portions are alternately arranged in axial symmetry about the axis of the stem, and further, a flat portion extending in the axial direction is formed in the upper portion of the stem to form an exhaust valve of the exhaust valve. It is characterized by preventing rotation.

On the lower surface of the intake valve, there is formed a bulge portion which is curved in a convex shape and has an outer surface which is a curved surface having a substantially streamlined shape.
Further, a plurality of substantially spiral groove portions and wall portions are alternately arranged axially symmetrically with respect to the axis of the stem in the umbrella portion which is the upper surface of the intake valve, and further, in the axial direction above the stem. The extended flat portion may be formed to prevent the intake valve from rotating.

Further, a screw-shaped groove having a winding direction which is the same as the winding direction of the substantially spiral groove provided on the umbrella portion of the exhaust valve is formed on the inner peripheral surface of the exhaust port, and On the inner peripheral surface of the intake port, a screw-shaped groove having the same winding direction as the winding direction of the substantially spiral groove provided on the umbrella portion of the intake valve is formed.

Further, in the bulging portion on the lower surface of the exhaust valve, a plurality of substantially spiral groove portions and wall portions are provided with respect to the center of the bulging portion so as to further promote the swirling flow of the exhaust gas flow. The plurality of substantially spiral groove portions and wall portions are arranged in the bulging portion on the lower surface of the intake valve so as to further promote the swirling flow of the intake gas flow. They are arranged axially symmetrically with respect to the center of the projecting portion.

A hollow portion is formed in the exhaust valve,
Metallic sodium may be enclosed in the hollow portion while leaving a void portion above. In addition, a hollow portion is formed in the intake valve,
Metallic sodium may be enclosed in the hollow portion while leaving a void portion above.

Next, the operation of the present invention will be described. When a downward force is applied to the stem of the exhaust valve and the stem moves downward, the exhaust valve opens. A convex curved bulging portion is formed on the lower surface of the exhaust valve, and the outer surface of the bulging portion is a substantially streamlined curved surface. Flows smoothly to the downstream side along the substantially streamlined curved surface of the bulging portion. Then, on the upper surface of the exhaust valve, a plurality of substantially spiral groove portions and wall portions are arranged in the umbrella portion in axial symmetry about the axis of the stem, and the upper portion of the stem extends in the axial direction. Since the flat portion is formed to prevent the exhaust valve from rotating, the exhaust gas flowing out from the upstream side flows into the substantially spiral groove and swirls smoothly along the curved surface of the groove. To do. Then, the exhaust gas flowing out from the substantially spiral groove portion is swirled and quickly discharged to the downstream side of the exhaust port.

[0011]

FIG. 1 shows a first embodiment of the present invention.
A description will be given based on FIG. FIG. 1 is a sectional view of an upper portion of a cylinder in a valve device for an internal combustion engine according to the present invention. In FIG. 1, 1 is an exhaust valve, 2 is a valve face,
3 is the stem of the exhaust valve 1, 5 is the exhaust port, 6 is the intake valve,
Reference numeral 7 indicates the intake valve stem, and 8 indicates the intake port. A piston 11 is reciprocally fitted in the cylinder 10 and a cylinder head 12 is fixed to the upper portion of the cylinder 10 via a gasket. An exhaust port 5 is formed inside the cylinder head 12,
An annular valve seat 13 is attached to the open end of the exhaust port 5 by a method such as casting or press fitting, and when the valve is closed, the outer peripheral edge of the valve face 2 of the exhaust valve 1 is annular. The exhaust port 5 and the combustion chamber are shut off by closely contacting each other. Similarly, an intake port 8 is formed inside the cylinder head 12, and an annular valve seat 15 is attached to the open end of the intake port 8 by a method such as casting or press fitting, and the valve closed state. In the above, the outer peripheral edge of the valve face 15 of the intake valve 6 is annularly adhered to the valve seat surface to block the intake port 8 from the combustion chamber.

On the lower surface of the exhaust valve 1, there is formed a bulging portion 16 which is curved in a convex shape toward the combustion chamber side, and the gas discharged when the exhaust valve 1 is opened is the bulging portion 16 of the bulging portion 16. The curved bulging portion 1 so that it smoothly flows to the downstream side along the outer peripheral surface.
The outer surface of 6 is formed in a substantially streamlined shape. In addition, the umbrella portion 17, which is the upper surface of the exhaust valve 1, has a plurality of substantially spiral grooves 1
8 are provided. A substantially spiral wall 20 is provided adjacent to the substantially spiral groove 18, and the wall 20 separates and partitions the substantially spiral groove 18 and the next groove 18.
A plurality of pairs of the groove 18 and the wall 20 are arranged axially symmetrically with respect to the axis C ₂ of the exhaust valve 1. Wall 20
Is highest at the lowermost end of the umbrella portion 17, is 0 at the uppermost end, and is smoothly and continuously connected to the stem 3 of the exhaust valve 1. The depth of the groove 18 is such that the portion in contact with the wall 20 is the umbrella portion 1
Deepest at the bottom of 7 and 0 at the top, exhaust valve 1
Is smoothly and continuously connected to the stem 3, but the depth in the circumferential direction is shallow with a smooth curved surface in the clockwise direction centering on the axis C ₂ , and the adjacent side ( It coincides with the ridge of the wall 20 (on the left side in the figure).

FIG. 2 is a view of the exhaust valve 1 in FIG. 1 as seen from the direction of arrow D. In the figure, a substantially spiral groove 18
And the substantially spiral wall 20 are 6 with respect to the axis C ₂ of the stem 3.
They are arranged axially symmetrically one by one. The spiral direction is clockwise from the outer peripheral portion of the exhaust valve 1, that is, from the vicinity of the valve face 2 toward the axis C ₂ , and therefore the flow of exhaust gas is also swirled clockwise toward the center. become. Further, the intake / exhaust valves 6 and 1 reciprocate in the cylinder according to the intake / exhaust stroke of the internal combustion engine, which is similar to the prior art, but the upper portion of the stem 3 of the exhaust valve 1 in the present embodiment is The cross-sectional shape is not circular but a so-called D-shaped cross section in which a flat portion 19 extending in the axial direction is formed. Since the insertion hole having the D-shaped cross section is formed, the exhaust valve 1 is prevented from rotating when reciprocating. Therefore,
The exhaust valve 1 has the stem 3 even if it receives a reaction force of the swirling flow of the exhaust gas.
It does not rotate around the axis C ₂ of.

Next, the operation of the first embodiment of the present invention will be described. Now, when a downward force is applied to the stem 3 of the exhaust valve 1 and the stem 3 moves downward, the exhaust valve 1 seated on the valve seat 13 is replaced by the exhaust valve 1.
And the exhaust valve 1 opens. Since a convexly curved bulging portion 16 is formed on the lower surface of the exhaust valve 1 and the outer surface of the bulging portion 16 is formed in a substantially streamlined shape, the lower surface of the exhaust valve 1 (upstream Side), the exhaust gas filled in the combustion chamber has a bulge 1 as shown by an arrow in FIG.
It smoothly flows out to the downstream side along the substantially streamlined curved surface of 6. Then, on the upper surface (downstream side) of the exhaust valve, a plurality of substantially spiral grooves 18 are formed in the umbrella portion 17, and the depth of the substantially spiral grooves 18 is the umbrella portion at a position in contact with the wall 20. 17
Is deepest at the lowermost end, becomes 0 at the uppermost end, and is smoothly and continuously connected to the stem 3. Further, the depth in the circumferential direction is a curved surface that is smooth in the clockwise direction about the axis C _2. It becomes shallower and coincides with the ridge of the wall 20 on the adjacent side (left side in the figure). Further, as shown in FIG. 2, the spiral direction is clockwise from the vicinity of the valve face 2 toward the axis C ₂ . Therefore, on the upper surface (downstream side) of the exhaust valve, the exhaust gas flowing out from the upstream side flows into the substantially spiral groove 18 from the vicinity of the valve face 2 and swirls along the curved surface of the groove 18 as shown by the arrow. It becomes a flow and smoothly turns clockwise in the direction of the axis C ₂ . Then, the exhaust gas flowing out from the substantially spiral groove 18 is discharged into the stem 3
Is swirled in the clockwise direction and is quickly discharged to the downstream side of the exhaust port 5. As described above, a large dead water area that has conventionally been generated in the lower portion of the exhaust valve is not formed, and a large separation area is not generated in the upper portion of the exhaust valve. Therefore, since the exhaust gas is smoothly discharged and the gas is exchanged efficiently, the pumping loss is reduced and the efficiency of the internal combustion engine can be improved.

FIG. 3 shows a second embodiment of the present invention. Further, by designating the same reference numerals for the structural parts common to the above-mentioned first embodiment,
A duplicate description will be omitted. The same applies to other embodiments described below. Although only the shape of the exhaust valve 1 is changed in the first embodiment described above, the shape of the intake valve 6 is also changed in the present embodiment based on the technical idea of the present invention. In the figure, a bulging portion 27 that is convexly curved toward the combustion chamber side is formed on the lower surface of the intake valve 6, and the intake gas that flows in when the intake valve 6 opens does not separate. The outer surface of the curved bulging portion 27 is formed in a substantially streamlined shape so that the bulging portion 27 smoothly flows into the cylinder 10 along the outer peripheral surface thereof. Further, the umbrella portion 28, which is the upper surface of the intake valve 6, is provided with a plurality of substantially spiral grooves 30. A substantially spiral wall 31 is provided adjacent to the substantially spiral groove 30, and the wall 31 separates and partitions the substantially spiral groove 30 and the next groove 30. A plurality of pairs of the groove 30 and the wall 31 are arranged axially symmetrically with respect to the axis C ₁ of the intake valve 6. The height of the wall 31, the depth of the groove 30, and the depth in the circumferential direction are the same as those of the exhaust valve 1 shown in the first embodiment, but the spiral direction is the exhaust valve 1. Different from

FIG. 4 is a view of the intake valve 6 in FIG. 3 as seen from the direction of arrow E. In the figure, a substantially spiral groove 30
And the substantially spiral wall 31 are 6 with respect to the axis C ₁ of the stem 7.
They are arranged axially symmetrically one by one. The spiral direction is opposite to that of the exhaust valve ₁ from the axis C ₁ of the stem 7 to the intake valve 6
Therefore, the flow of the intake gas also swirls clockwise toward the outer peripheral portion of the intake valve 6. Further, the intake / exhaust valves 6 and 1 reciprocate in the cylinder according to the intake / exhaust stroke of the internal combustion engine, which is similar to the prior art, but the upper portion of the stem 7 of the intake valve 6 in the present embodiment is The cross-sectional shape is not circular but a so-called D-shaped cross section in which a flat portion 32 extending in the axial direction is formed. Since a fitting insertion hole having a D-shaped cross section is formed, the intake valve 6 is prevented from rotating when reciprocating. Therefore, the intake valve 6 does not rotate around the axis C ₁ of the stem 7 even if it receives a reaction force of the swirling flow of the intake gas.

Therefore, when the intake valve 6 is opened, a plurality of substantially spiral grooves 30 are formed in the umbrella portion 28 of the intake valve 6, so that the intake gas flow coming from the downstream side is indicated by the arrow. As shown by, the intake gas flowing in a clockwise swirl flow smoothly through the intake port 8 and flowing out from the substantially spiral groove 30 is substantially flowed in the bulging portion 27 formed on the lower surface of the intake valve 6. While swirling along the linear outer surface as indicated by the arrow, it smoothly and swiftly flows into the cylinder 10 without causing separation. Therefore, the gas is efficiently inhaled,
The so-called pumping loss is reduced and the swirling flow promotes the mixing of air and fuel gas, so that the combustion is efficiently performed, so that the efficiency of the internal combustion engine can be improved.

FIG. 5 shows a third embodiment of the present invention. The third embodiment corresponds to an improved valve device for an internal combustion engine according to the second embodiment. 8 and the exhaust port 5 are provided with screw-shaped grooves 33 and 35 on the inner peripheral surfaces thereof. The winding direction of the groove 33 is the umbrella portion 28 of the intake valve 6.
The winding direction of the exhaust valve 1 is the same as the winding direction of the substantially spiral groove 30 formed in the exhaust valve 1.
The winding direction is the same as the winding direction of the substantially spiral groove 18 formed in the umbrella portion 17. Each groove 33 and 3
5 are the intake ports 8 as shown by the solid arrows, respectively.
Of the intake gas and the swirling flow of the exhaust gas in the exhaust port 5 as indicated by the one-dot chain line arrow, and further, the grooves 33 and 35 smoothly flow the intake gas into the cylinder and exhaust the exhaust gas. This allows smooth outflow to the downstream side of the exhaust port.
Moreover, at the time of inhaling the intake gas, the swirling flow also promotes the mixing of the air and the fuel, and a good combustion state can be obtained. Further, in forming the screw-shaped grooves 33 and 35, it is sufficient to cut from the inlet side and the outlet side of the intake port 8 or the exhaust port 5 to the extent that the grooves 33 and 35 can be cut by a screw cutting tool. It is possible to achieve the purpose of obtaining a swirling flow even if the shape is not continuous as in the case of screwing. Therefore, it is possible to obtain the above-mentioned effects without increasing the price with a simple manufacturing method. The screw-shaped groove may be provided only on the inner peripheral surface of the exhaust port.

FIG. 6 shows a fourth embodiment of the present invention. The fourth embodiment corresponds to an improved valve device for an internal combustion engine according to the third embodiment. 6 and the bulging portions 27 and 16 on the lower surface of the exhaust valve 1 are provided with substantially spiral grooves 36 and 37.

FIG. 7 is a front view of the bulging portion 27 of the lower surface of the intake valve 6 as seen from the cylinder 10 side. The plurality of substantially spiral grooves 36 and the wall 38 are located with respect to the center of the bulging portion 27. Eight pieces are alternately arranged in axial symmetry, and the spiral direction is counterclockwise from the outer peripheral portion of the bulging portion 27 toward the center. This further promotes the direction of the intake gas flow toward the swirl flow in the third embodiment, as shown by the solid arrow in FIG. 7, increasing the strength of the swirl flow and producing a greater effect. Obtainable.

FIG. 8 is a front view of the bulging portion 16 on the lower surface of the exhaust valve 1 as seen from the cylinder 10 side, and the plurality of substantially spiral grooves 37 and the wall 38 are arranged with respect to the center of the bulging portion 16. Eight pieces are alternately arranged in axial symmetry, and the spiral direction is counterclockwise from the center of the bulging portion 16 toward the outer peripheral portion. This further promotes the exhaust gas flow direction to the swirl flow direction in the third embodiment, as indicated by the one-dot chain line arrow in FIG. 7, thereby increasing the swirl flow intensity and providing a greater effect. Can be obtained. The substantially spiral groove may be provided only in the exhaust valve.

Next, another embodiment of the exhaust valve applied to the valve device for an internal combustion engine of the present invention will be described.
FIG. 9 is a half sectional view showing another embodiment of the exhaust valve. FIG.
The external shape of the exhaust valve 1 shown in (1) is the same as that of the exhaust valve shown in the first embodiment, except that the exhaust valve 1 is hollow and metallic sodium 21 is enclosed inside the exhaust valve. Further, a void 22 is provided above the metallic sodium 21 so that the metallic sodium 21 can expand in the void 22 at high temperature. By enclosing the metallic sodium 21, it is possible to prevent an increase in thermal deformation due to an increase in the thickness of the lower portion 23 of the exhaust valve 1 applied to the internal combustion engine of the present invention as compared with the conventional exhaust valve. In addition, the weight of the exhaust valve 1 as a whole can be reduced due to the low specific gravity of the metallic sodium 21. Also,
In order to enclose the metallic sodium 21, the exhaust valve 1 is configured by being divided into a valve body portion 25 having a hollow portion and a solid portion 26 forming a part of the stem, and a hollow portion in the hollow portion of the valve body portion 25. After filling the metallic sodium 21 with 22 left, the solid portion 26 may be hermetically fixed to the valve body 25 by welding or the like. Further, although the exhaust valve has been described in the present embodiment, it goes without saying that it can be applied to the intake valve.

[0023]

Since the present invention is configured as described above, it has the following effects.

Since the lower surface of the exhaust valve is formed with a bulging portion which is curved in a convex shape and the outer surface of which is formed into a substantially streamlined curved surface,
In the lower part of the exhaust valve, the exhausted gas smoothly flows out along a curved surface having a substantially streamlined shape, and a large dead water region does not occur in the lower part unlike the conventional exhaust valve. Further, a plurality of substantially spiral groove portions and wall portions are alternately arranged axially symmetrically with respect to the stem axial center in the umbrella portion which is the upper surface of the exhaust valve. Since a flat portion extending in the direction is formed to prevent rotation of the exhaust valve, the exhaust gas flow flows into the substantially spiral groove portion in the upper portion of the exhaust valve and becomes a swirling flow along the curved surface of the groove portion. Smoothly and quickly,
Unlike the conventional case, a large peeling area does not occur above the exhaust valve. Therefore, exhaust gas is efficiently discharged, so that pumping loss is reduced and the efficiency of the internal combustion engine can be improved.

Further, a plurality of substantially spiral groove portions and wall portions are alternately arranged axially symmetrically with respect to the axial center of the stem in the umbrella portion which is the upper surface of the intake valve. Since a flat portion extending in the axial direction is formed to prevent rotation of the intake valve, the intake gas flow that has flowed in from the upstream side becomes a swirl flow and flows into the substantially spiral groove portion, and On the lower surface of the intake valve, there is formed a bulging portion which is curved in a convex shape and the outer surface of which is formed into a substantially streamlined curved surface. Therefore, the intake gas flowing out from the substantially spiral groove portion is substantially bulged. It swirls along the streamlined outer surface and smoothly and quickly flows into the cylinder without separation. Therefore, the gas is efficiently sucked, so-called pumping loss is reduced, and the swirling flow promotes the mixing of the air and the fuel gas, so that the combustion is efficiently performed and the efficiency as the internal combustion engine is improved. be able to.

Since a screw-shaped groove having the same winding direction as the winding direction of the substantially spiral groove provided on the umbrella portion of the exhaust valve is formed on the inner peripheral surface of the exhaust port, The swirling of the swirling flow of the exhaust gas can be promoted, and the exhaust gas can be smoothly discharged. In addition, since a screw-shaped groove having the same winding direction as the winding direction of the substantially spiral groove provided on the umbrella portion of the intake valve is formed on the inner peripheral surface of the intake port, the intake gas in the intake port The swirling of the swirling flow can be promoted, the mixing of the air and the fuel is also promoted by the swirling flow, and a good combustion state can be obtained.

Further, in the bulging portion on the lower surface of the exhaust valve, a plurality of substantially spiral groove portions and wall portions are alternately arranged in axial symmetry with respect to the center of the bulging portion. The swirl flow can be further promoted, and a plurality of substantially spiral groove portions and wall portions are alternately arranged axially symmetrically with respect to the center of the bulging portion in the bulging portion on the lower surface of the intake valve. Therefore, the swirl flow of the suction gas flow can be further promoted.

Further, since a hollow portion is formed in the intake valve and the exhaust valve, and metallic sodium is sealed in the hollow portion while leaving a void portion above, the thickness of each valve lower portion is smaller than that of the conventional valve. As a result, it is possible to prevent an increase in thermal deformation due to the increase in the weight of the valve, and it is possible to reduce the weight of the valve as a whole due to the low specific gravity of metallic sodium.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a valve device for an internal combustion engine of the present invention.

FIG. 2 is an arrow view of the exhaust valve in FIG. 1 as viewed in the direction of arrow D.

FIG. 3 is a sectional view showing a second embodiment of the present invention.

4 is a view of the intake valve in FIG. 3 as seen from the direction of arrow E. FIG.

FIG. 5 is a cross-sectional view showing a third embodiment of the present invention.

FIG. 6 is a sectional view showing a fourth embodiment of the present invention.

FIG. 7 is a front view of the bulging portion on the lower surface of the intake valve as viewed from the cylinder side.

FIG. 8 is a front view of the bulging portion on the lower surface of the exhaust valve as seen from the cylinder side.

FIG. 9 is a half cross-sectional view showing another embodiment of the exhaust valve applied to the valve device for an internal combustion engine of the present invention.

FIG. 10 is a sectional view of a conventional valve device for an internal combustion engine.

[Explanation of symbols]

 1 ... Exhaust valve 3 ... Stem 5 ... Exhaust port 6 ... Intake valve 7 ... Stem 8 ... Intake port 16,27 ... Swelling part 17, 28 ... Umbrella part 18, 30 ... Groove 19, 32 ... Flat part 20, 31 ... Wall 21 ... Metal sodium 22 ... Void 33 ... Intake port groove 35 ... Exhaust port groove 36 ... Intake valve groove 37 ... Exhaust valve groove 38 ... Intake valve wall 39 ... Exhaust valve wall

Claims (8)

[Claims] 1. A valve device for an internal combustion engine, comprising an intake valve having a stem provided in an intake port and an exhaust valve having a stem provided in an exhaust port, wherein a lower surface of the exhaust valve is curved in a convex shape. An outer surface is formed with a bulging portion having a substantially streamlined curved surface, and a plurality of substantially spiral groove portions and wall portions are provided in the umbrella portion which is the upper surface of the exhaust valve. A valve device for an internal combustion engine, wherein the exhaust valve is prevented from rotating by further forming an axially extending flat portion at an upper portion of the stem. 2. A bulging portion which is convexly curved and whose outer surface forms a substantially streamlined curved surface is formed on the lower surface of the intake valve, and the umbrella portion which is the upper surface of the intake valve is formed on the lower surface. A plurality of substantially spiral groove portions and wall portions are alternately arranged axially symmetrically with respect to the axis of the stem, and further, a flat portion extending in the axial direction is formed on the upper portion of the stem to form the intake valve. 2. The valve device for an internal combustion engine according to claim 1, wherein the valve device is prevented from rotating. 3. A screw-shaped groove having the same winding direction as the winding direction of the substantially spiral groove provided on the umbrella portion of the exhaust valve is formed on the inner peripheral surface of the exhaust port. The valve device for an internal combustion engine according to claim 1, which is characterized in that. 4. A screw-shaped groove is formed on the inner peripheral surface of the exhaust port, the screw-shaped groove having the same winding direction as the winding direction of the substantially spiral groove provided in the umbrella portion of the exhaust valve. The screw-shaped groove having the same winding direction as the winding direction of the substantially spiral groove provided on the umbrella portion of the intake valve is formed on the inner peripheral surface of the intake port. A valve device for an internal combustion engine as described. 5. A plurality of substantially spiral groove portions and walls are formed in the bulging portion of the lower surface of the exhaust valve with respect to the center of the bulging portion so as to further promote a swirling flow of the exhaust gas flow. 4. Arranged alternately in axial symmetry, Claim 1 or Claim 3
A valve device for an internal combustion engine according to item 1. 6. The bulging portion on the lower surface of the exhaust valve is provided with a plurality of substantially spiral groove portions and wall portions with respect to the center of the bulging portion so as to further promote a swirling flow of the exhaust gas flow. The plurality of substantially spiral grooves and walls are arranged in the bulging portion on the lower surface of the intake valve so as to further promote the swirling flow of the intake gas flow. The valve device for an internal combustion engine according to claim 2 or 4, wherein the valve devices are arranged axially symmetrically with respect to the center of the projecting portion. 7. The exhaust valve according to claim 1, wherein the exhaust valve is formed with a hollow portion, and metallic sodium is enclosed in the hollow portion while leaving a void portion above. The valve device for an internal combustion engine according to claim 1. 8. The method according to claim 2, wherein the intake valve is formed with a hollow portion, and metallic sodium is enclosed in the hollow portion while leaving a void portion above. The valve device for an internal combustion engine according to claim 6.