JP2010112227A - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine capable of preventing a fuel from being formed in droplets. <P>SOLUTION: This internal combustion engine comprises an intake port 12 formed in a cylinder head 10, an intake valve 14 for opening and closing between a combustion chamber 11 and the opening 17 of the intake port 12, and a valve seat 18 which is provided in the state of coming into contact with an arrangement part 20 formed at the opening 17 of the intake port 12 and which closes the opening 17 of the intake port 12 when coming into contact with the bevel part 16 of the intake valve 14. A gap part where the arrangement part 20 and the valve seat 18 which do not come into contact with each other is formed on the inside of a cutout groove 18a by providing the cutout groove 18a in the valve seat 18. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an internal combustion engine.

  As an internal combustion engine, an intake port injection type is known, and in this intake port injection type internal combustion engine, a fuel injection device is provided in the intake port and fuel is injected toward the intake valve. ing.

Japanese Patent Publication No. 61-229908 Japanese Patent Publication No. 61-229926

  In an intake port injection type internal combustion engine, the fuel injected toward the intake valve may become droplets at the time of cold start. When the fuel in droplets enters the cylinder as it is, the HC in the exhaust gas increases. Therefore, in order to reduce the HC in the exhaust gas, how to vaporize the injected fuel becomes important. Normally, the intake valve has heat input from the fuel (combustion gas) combusted in the cylinder, and if this heat can be used effectively, it is possible to suppress fuel droplet formation. However, the intake valve is in contact with the cylinder head via the valve seat, and the heat input to the intake valve is taken away by the cylinder head with a large heat capacity until the entire internal combustion engine is warmed up. It was difficult to raise the intake valve to a high temperature (fuel vaporization temperature), and as a result, it was difficult to suppress fuel droplet formation.

  The present invention has been made in view of the above problems, and an object thereof is to provide an internal combustion engine that suppresses fuel droplet formation.

An internal combustion engine according to a first invention for solving the above-described problem is
An intake port formed in the cylinder head of the internal combustion engine;
An intake valve that opens and closes between a combustion chamber of the internal combustion engine and an opening of the intake port;
A valve seat that is provided in contact with an arrangement portion formed in the opening of the intake port, and that closes the opening of the intake port when in contact with an umbrella portion of the intake valve;
Between the said arrangement | positioning part and the said valve seat, the space | gap part from which these both become non-contact is provided, It is characterized by the above-mentioned.

An internal combustion engine according to a second invention for solving the above-described problems is
In the internal combustion engine according to the first aspect,
The gap portion is formed inside a notch portion in which at least a part of the valve seat is notched.

An internal combustion engine according to a third invention for solving the above-described problem is
In the internal combustion engine according to the first or second invention,
The void portion is formed inside a portion where at least a part of the arrangement portion is dug.

An internal combustion engine according to a fourth invention for solving the above-described problem is
In the internal combustion engine according to any one of the first to third inventions,
A gas having a low thermal conductivity is sealed in the gap.

An internal combustion engine according to a fifth invention for solving the above-described problem is
In the internal combustion engine according to any one of the first to third inventions,
The inside of the gap is in a reduced pressure state.

An internal combustion engine according to a sixth invention for solving the above-described problem is
In the internal combustion engine according to any one of the first to fifth inventions,
The intake valve is characterized in that a portion of the umbrella portion that is in contact with the valve seat is formed from a material having low thermal conductivity, and another portion of the umbrella portion is formed from a material having high thermal conductivity. To do.

  According to the present invention, since the gap is provided in at least one of the valve seat or the cylinder head and the contact area between the valve seat and the cylinder head is reduced, the inside of the gap has a low thermal conductivity. Therefore, the temperature of the intake valve after the cold start can be increased. Therefore, fuel adhesion (droplet formation) to the intake valve can be suppressed, and as a result, HC emission can be reduced.

  In addition, according to the present invention, the portion of the umbrella portion of the intake valve that is in contact with the valve seat is formed of a low thermal conductivity material, and the other portion of the umbrella portion is formed of a high thermal conductivity material. The temperature of the later intake valve can be further increased. Therefore, fuel adhesion (droplet formation) to the intake valve can be further suppressed, and as a result, HC emission can be further reduced.

  Hereinafter, an embodiment of an internal combustion engine according to the present invention will be described in detail with reference to FIGS.

Example 1
FIG. 1 is a schematic configuration diagram showing an example of an embodiment of an internal combustion engine according to the present invention.
As shown in FIG. 1, an intake port 12 for supplying air to a combustion chamber 11 is formed in a cylinder head 10 of an internal combustion engine (hereinafter referred to as an engine). In the intake port injection type engine, a fuel injection device (hereinafter referred to as an injector) 13 is provided in the intake port 12. An intake valve 14 is provided at an opening portion (opening portion 17) of the intake port 12 to the combustion chamber 11, and the intake valve 14 is opened and closed between the combustion chamber 11 and the opening portion 17 of the intake port 12. Open and close.

  The intake valve 14 includes a stem portion 15 that transmits a driving operation of a cam or the like (not shown), and an umbrella portion 16 that is supported by the stem portion 15 and opens and closes an opening portion 17. The opening 17 is provided with a ring-shaped valve seat 18 in contact with the arrangement portion 20 formed on the cylinder head 10 side.

  During the closing operation of the intake valve 14, the rear surface of the umbrella portion 16 (the upstream surface of the intake port 12) is brought into close contact with the valve seat 18, thereby closing the opening 17 of the intake port 12, and the combustion chamber 11. On the other hand, the combustion chamber 11 is hermetically sealed by disabling the intake port 12.

  On the other hand, when the intake valve 14 is opened, the umbrella portion 16 is moved to the combustion chamber 11 side by the stem portion 15, and a gap is formed between the back surface of the umbrella portion 16 and the valve seat 18. On the other hand, the intake port 12 is communicated to supply air to the combustion chamber 11. At this time, the fuel f injected from the injector 13 toward the back surface of the umbrella portion 16 is supplied to the combustion chamber 11 together with air. Thereafter, the fuel f and air supplied to the combustion chamber 11 are ignited and burned by a spark plug 19 provided in the ceiling portion of the combustion chamber 11 (bottom surface portion of the cylinder head 10).

  As described above, in an intake port injection type internal combustion engine, the fuel injected toward the intake valve may be formed into droplets at the time of cold start. Therefore, in this embodiment, the shape of the valve seat 18 is devised so that the heat input to the umbrella portion 16 is not taken away by the cylinder head 10 side.

  Specifically, the ring-shaped valve seat 18 is provided with a notched groove 18a (notched portion) having a rectangular cross-sectional shape that is notched along the outer peripheral direction of the portion in contact with the arrangement portion 20 of the cylinder head 10. And an arrangement portion 20 are provided with a gap portion in which they are not in contact with each other. Such a notch groove 18a can be formed by applying a simple process to an existing valve seat including a notch groove 21a described later.

  In addition, although this notch groove 18a is provided in the perimeter of the valve seat 18, and forms the space | gap part in the perimeter, it is not restricted to a perimeter, At least one part of the outer periphery of the valve seat 18 is formed. A notched portion that is notched may be provided, and a gap may be formed in an inner space formed by the notched portion. Further, it is desirable that the valve seat 18 itself be formed from a material having as low a thermal conductivity as possible.

  With the above configuration, the contact area of the valve seat 18 with the cylinder head 10 is reduced, the amount of heat transfer from the valve seat 18 to the cylinder head 10 is reduced, and the heat input to the umbrella portion 16 is transferred to the cylinder head 10 side. It can be made difficult to take away. Therefore, even immediately after the cold start, since the heat input from the combustion gas remains in the umbrella portion 16, the temperature of the umbrella portion 16 can be raised to the highest possible temperature (the vaporization temperature of the fuel), and the injected fuel Vaporization is promoted and droplet formation is suppressed. As a result, the exhaust gas HC is reduced.

  Here, the notch groove 18a (notch part) is provided at one location on the upper end side far from the combustion chamber 11, but such a notch groove (notch part) can be used if the required strength of the valve seat 18 can be maintained. May be provided at a plurality of locations so that the contact area of the valve seat 18 to the cylinder head 10 becomes smaller.

  In addition to the notch groove 18a having a rectangular cross-sectional shape, as shown in FIG. 2, in the ring-shaped valve seat 21, a fan-shaped cross-sectional shape such as a quadrant is formed along the outer peripheral direction of the portion in contact with the cylinder head 10. The notch groove 21a may be provided so that the contact area of the valve seat 21 to the cylinder head 10 may be reduced.

  Furthermore, the valve seats 18 and 21 are attached to the arrangement part 20 by press-fitting. At this time, the valve seats 18 and 21 are in an atmosphere state made of a gas having a low thermal conductivity or in a reduced pressure state (or a vacuum state). And a state in which a gas having a low thermal conductivity is sealed in a gap formed between the arrangement portion 20 and the notch grooves 18a and 21a, or the inside of the gap is reduced in pressure (or in a vacuum state). Then, heat transfer to the cylinder head 10 side may be further reduced.

(Example 2)
FIG. 3 is a schematic configuration diagram showing another example of the embodiment of the internal combustion engine according to the present invention. In this embodiment, the configuration of the intake valve (umbrella) is further devised based on the configuration of the first embodiment. Therefore, the same components as those shown in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In the present embodiment, by devising the configuration of the umbrella portion 31 of the intake valve 14, the amount of heat transferred from the combustion gas to the umbrella portion 31 is increased, and the heat input to the umbrella portion 31 is increased by the valve. Heat is not transferred to the sheet 18 side.

  Specifically, in the umbrella portion 31, only the contact portion 33 that is a portion that contacts the valve seat 18 is formed from a material having low thermal conductivity, and the other portion of the umbrella portion 31, that is, the combustion chamber 11. A main part 32 composed of a surface that receives heat input of combustion gas and a back surface from which fuel is injected from the injector 13 is formed from a material having high thermal conductivity.

  More specifically, as shown in the cutaway view of the umbrella portion 31 shown in FIG. 4, a portion where the umbrella portion 31 contacts the valve seat 18 is cut out in the outer peripheral direction to form a flange portion 34, and the rear surface of the flange portion 34. A ring-shaped contact portion 33 is fitted and welded to the side (valve seat 18 side).

  With the above configuration, in addition to reducing the heat transfer from the valve seat 18 side to the cylinder head 10 side, the amount of heat transferred from the combustion gas to the umbrella portion 31 is increased, and the valve from the umbrella portion 31 side is increased. Heat transfer to the sheet 18 side can also be reduced. Therefore, even immediately after the cold start, since the heat input from the combustion gas remains in the umbrella portion 31, the temperature of the umbrella portion 31 can be increased to a higher temperature (fuel vaporization temperature) earlier, and the injected fuel Vaporization is further promoted, and droplet formation is further suppressed. As a result, the exhaust gas HC is further reduced.

  In order to prevent the contact portion 33 from coming off, as shown in FIG. 5, a stepped step portion 35 is formed on the outer peripheral portion of the main portion 33 of the umbrella portion 31 and corresponds to the shape of the step portion 35. A stepped stepped portion 36 is also formed on the inner peripheral portion of the contact portion 33, and the stepped portion 35 and the stepped portion 36 are fitted to each other and welded together, so that the main portion is made of a material having a high thermal conductivity. The joint between the portion 32 and the contact portion 33 made of a material having low thermal conductivity may be firmly fixed.

(Example 3)
FIG. 6 is a schematic configuration diagram showing still another example of the embodiment of the internal combustion engine according to the present invention. In addition, since a present Example is based on the structure of Example 1, the same code | symbol is attached | subjected about the same thing as the structure shown in Example 1, and the overlapping description is abbreviate | omitted.

  In the present embodiment, the configuration of the arrangement portion 20 on the cylinder head 10 side is devised so that the heat input to the umbrella portion 31 is not transferred to the cylinder head 10 side.

  Specifically, in the arrangement portion 20, a dug groove 41 (digging portion) having a rectangular cross-sectional shape in which a portion that contacts the upper end side (upstream side of the intake port 12) of the valve seat 18 is dug along the circumferential direction. A gap is formed between the valve seat 18 and the arrangement portion 20 so that they are not in contact with each other. Such a digging groove 41 may be cut and formed by deeply digging a part of the opening 17 in the circumferential direction when the opening 17 is cut and formed.

  In addition, although this digging groove 41 is provided in the perimeter of the arrangement | positioning part 20, and forms the space | gap part in the perimeter, it is not restricted to a perimeter and contacts the upper end side of the valve seat 18. It is also possible to dig at least part of the arrangement portion 20 to provide a digging portion, and to form a void in an inner space formed by the digging portion.

  With the above configuration, the contact area of the cylinder head 10 with the valve seat 18 is reduced, the amount of heat transfer from the valve seat 18 to the cylinder head 10 is reduced, and the heat input to the umbrella portion 16 is transferred to the cylinder head 10 side. It can be made difficult to take away. Therefore, even immediately after the cold start, since the heat input from the combustion gas remains in the umbrella portion 16, the temperature of the umbrella portion 16 can be raised to the highest possible temperature (the vaporization temperature of the fuel), and the injected fuel Vaporization is promoted and droplet formation is suppressed. As a result, the exhaust gas HC is reduced.

  Here, the digging groove 41 (digging portion) is provided at one place where the digging groove 41 comes into contact with the upper end side of the valve seat 18. (Duging portions) may be provided at a plurality of locations so that the contact area of the placement portion 20 with the valve seat 18 is further reduced.

  Further, in FIG. 6, the valve seat 18 side does not have a notch groove (or notch portion) that forms a gap, but the valve seat 18 also has a notch groove 18a (or notch portion) as shown in FIG. And the digging groove 41 and the notch groove 18a (or the digging part and the notch part) may be arranged so as to face each other or be adjacent to each other to form a larger gap part. That is, you may combine a present Example and Example 1. FIG. Further, it may be combined with the second embodiment. In addition, although the direction shown in FIG. 7 is formed larger than the direction shown in FIG. 6, the trench 41 is advantageous in that the contact area can be made smaller. In this way, by combining with other embodiments, fuel droplet formation may be further suppressed to further reduce exhaust gas HC.

  The internal combustion engine according to the present invention is suitable for an intake port injection type internal combustion engine.

It is a schematic structure figure showing an example of an embodiment of an internal-combustion engine concerning the present invention. It is sectional drawing which shows the modification of the valve seat in the internal combustion engine which concerns on this invention shown in FIG. It is a schematic block diagram which shows another example of embodiment of the internal combustion engine which concerns on this invention. FIG. 4 is a cutaway view showing an umbrella portion of an intake valve in the internal combustion engine according to the present invention shown in FIG. 3. FIG. 5 is a cutaway view showing a modification of the umbrella portion of the intake valve in the internal combustion engine according to the present invention shown in FIG. 4. It is a schematic block diagram which shows another example of embodiment of the internal combustion engine which concerns on this invention. It is a schematic block diagram which shows the modification of the internal combustion engine which concerns on this invention shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cylinder head 11 Combustion chamber 12 Intake port 13 Injector 14 Intake valve 15 Stem part 16, 31 Umbrella part 17 Opening part 18, 21 Valve seat 18a, 21a Notch groove 19 Spark plug 20 Arrangement part 32 Main part 33 Contact part 41 Digging Part

Claims (6)

An intake port formed in the cylinder head of the internal combustion engine;
An intake valve that opens and closes between a combustion chamber of the internal combustion engine and an opening of the intake port;
A valve seat that is provided in contact with an arrangement portion formed in the opening of the intake port, and that closes the opening of the intake port when in contact with an umbrella portion of the intake valve;
An internal combustion engine characterized in that a gap is formed between the arrangement portion and the valve seat so that they are not in contact with each other. The internal combustion engine according to claim 1,
2. The internal combustion engine according to claim 1, wherein the gap portion is formed inside a notch portion in which at least a part of the valve seat is notched. The internal combustion engine according to claim 1 or 2,
The internal combustion engine, wherein the gap portion is configured inside a portion in which at least a part of the arrangement portion is dug. The internal combustion engine according to any one of claims 1 to 3,
An internal combustion engine characterized in that a gas having low thermal conductivity is sealed in the gap. The internal combustion engine according to any one of claims 1 to 3,
An internal combustion engine characterized in that the inside of the gap is in a reduced pressure state. The internal combustion engine according to any one of claims 1 to 5,
The intake valve is characterized in that a portion of the umbrella portion that is in contact with the valve seat is formed from a material having low thermal conductivity, and another portion of the umbrella portion is formed from a material having high thermal conductivity. An internal combustion engine.

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