JPH0518566Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Industrial application field] This invention is suitable for indirect or direct use in vehicles equipped with internal combustion engines, vehicles such as trailers, domestic rooms, drying rooms, offices, etc. It relates to combustion equipment applicable to heating equipment, drying equipment, boilers, water heaters, greenhouses, etc.

[Conventional technology]

Conventionally, for example, to heat the interior of a vehicle, cooling water from the internal combustion engine is taken out through hot water piping, guided to a heater device, where heat is exchanged indirectly, and warm air is sent into the vehicle to heat the interior of the vehicle. There is something.

Furthermore, there is a heating device for a vehicle (see, for example, Japanese Patent Application Laid-Open No. 60-252018) that heats the room by the amount of heat generated by burning fuel in a burner, ie, a combustor, regardless of the internal combustion engine.

Furthermore, an engine heating system (for example, a heating system for an engine that supplies combustion gas from a combustor to the intake port of the engine via a heat exchanger and guides the air heated by the heat exchanger to the passenger compartment) -Refer to Publication No. 79864).

Examples of prior art include Japanese Patent Application No. 60-207330 (Japanese Unexamined Patent Publication No. 62-69009) and Utility Model Application No. 1987-198322 filed by the present applicant.
There is a combustor as disclosed in Japanese Patent Publication No.

The combustor disclosed in JP-A-62-69009 will be summarized with reference to FIG. 3. The combustor 50 has a vaporizing chamber 54 formed inside the combustion tube 51 by a partition plate 52 having a plurality of notched passages 53 on the periphery.
and a combustion chamber 56 having an air introduction hole 55 in the peripheral wall thereof, a combustor equipped with a fuel vaporization device having a nozzle 57 for ejecting vaporized fuel opening into the vaporization chamber 54, and having fins 58 on the outer circumferential surface. Disclosed. In the figure, 59 indicates a lid plate.

Further, the combustor disclosed in the above-mentioned Japanese Utility Model Publication No. 198322/1988 will be summarized with reference to FIG.
The combustor 60 partitions the combustion tube 61 into a vaporization chamber 64 and a combustion chamber 66 by a partition plate 62 having an opening 63, and forms the vaporization chamber 64 in the upper part of the combustion tube 61 and the combustion chamber 66 in the lower part, The fuel injection pipe 70 of the vaporizer 65 that penetrates the combustion chamber 66 is opened into the vaporization chamber 64, and the vaporization chamber 64 is provided with an ignition glow plug 67. The combustor 60 has an air introduction hole 68 formed at the bottom of the combustion chamber 66, and a combustion gas outlet 69 formed at the bottom of the combustion chamber 66.

[Problem that the invention attempts to solve]

However, in those systems that use the internal combustion engine's cooling water to heat the room, the temperature of the cooling water rises slowly, so it takes a long time for the heater body to send out hot air, and during that time the heater is turned off. There is almost no heating function.

In addition, for automobile heating systems or engine heating systems that use a combustor independent of the internal combustion engine, combustion cycles, exhaust gas processing, etc. require time and effort, and complex mechanisms and control devices are required. There are problems such as:

Regarding the combustor 50, regarding the introduction of combustion air, it cannot be said that the introduction of combustion air into the combustion tube 51 is sufficient, and the flow of the vaporized fuel injected into the vaporization chamber 54 is Mist carbon may be generated, and vaporized fuel may liquefy and adhere to the inside of the combustion tube 51 or
However, there are insufficient measures to prevent the generation of carbon by creating a good mixture of combustion air and vaporized fuel after introduction. It is something that cannot be said.

The combustor 60 is a vertical combustion tube 61, which homogenizes the distribution of the mixture of air and vaporized fuel to prevent fuel accumulation due to incomplete combustion or poor vaporization. Although it is possible to vaporize the fuel immediately and completely burn the fuel even if fuel accumulation occurs, the mist carbon This is not sufficient in terms of preventing the vaporized fuel from becoming liquefied again from adhering to the combustion tube 61, especially the combustion chamber 66, and generating carbon.

Therefore, the purpose of this invention is to solve the above problems.In a combustion device that rapidly vaporizes fuel and burns the vaporized fuel by mixing it with combustion air, the combustion air is Introduced from the inlet pipe, configured so that it can be easily introduced into the combustion cylinder from around the combustion cylinder smoothly and in a low resistance state,
In addition, a portion of the combustion air is introduced into the vaporization chamber to ignite the vaporized fuel very well, and furthermore, the vaporized fuel and combustion air are ideally mixed in the vaporization chamber to generate a mixture and combustion. It is an object of the present invention to provide a combustion device that allows combustion to flourish.

That is, this combustion device prevents the fuel ejected from the vaporization device from directly colliding with the vaporization chamber forming plate and causing the vaporized fuel to adhere to the wall surface, thereby smoothing the flow of the vaporized fuel ejected into the vaporization chamber. , the vaporized fuel mixes well with the air that flows in from the combustion chamber side through the opening, ignites it, prevents the generation of mist carbon, and prevents the generation of carbon that tends to adhere to the wall inside the combustion cylinder. Even if carbon is generated, it can be completely combusted by supplying fresh air.

[Means for solving problems]

In order to achieve the above object, this invention is constructed as follows. That is, this invention consists of a combustion tube with a large number of air introduction holes, a partition plate that divides the inside of the combustion tube into a combustion chamber and a vaporization chamber and has an opening that communicates the two chambers, and a vaporization tube inside the combustion chamber. a vaporizer in which a pipe is disposed and a fuel injection port is opened in the vaporization chamber; a vaporization chamber forming plate provided in the combustion cylinder and forming an inner wall surface of the vaporization chamber; and a vaporization chamber formed opposite to the fuel injection port. The present invention relates to a combustion device characterized by having an umbrella-shaped fuel spray diffusion plate with a hemispherical cross section installed on a plate.

[Effect]

The combustion device according to this invention is constructed as described above and operates as follows. That is, in this combustion device, a combustion tube is divided into a combustion chamber and a vaporization chamber, a fuel injection port of the vaporization device is opened into the vaporization chamber, and an umbrella with a hemispherical cross section is provided in the vaporization chamber opposite to the fuel injection port. Since the shaped fuel spray diffusion plate is installed, the liquid fuel is immediately and rapidly vaporized into vaporized fuel by the vaporization device, and the vaporized fuel injected from the fuel injection port into the vaporization chamber is fuel injection. The jet stream diffuses backward in the radial direction along the direction, and its jet stream line is unobstructed, forming a smooth flow.

In this combustion device, the vaporized fuel ejected from the fuel injection port of the vaporization device does not collide directly with the wall surface of the vaporization chamber and is cooled, but instead flows through the fuel spray diffusion plate formed into an umbrella shape with a hemispherical cross section. The vaporized fuel of the swirling flow is diffused from the protruding tip along the umbrella-shaped curved surface and flows smoothly to form a swirling flow, and the vaporized fuel of the swirling flow is combined with the combustion air that has flowed from the combustion chamber through the opening of the partition plate. Since the vaporized fuel is well mixed and does not collide directly with the wall surface of the vaporization chamber, the vaporized fuel is not liquefied by cooling in the vaporization chamber, and mist carbon is not generated.

Moreover, fresh air is introduced so as to follow the swirling flow, that is, to promote the swirling flow, through the air introduction hole located upstream of the air straightening plate, which is a part where vaporized fuel is likely to liquefy and generate carbon. It is possible to prevent the generation of carbon or to completely burn the generated carbon.

〔Example〕

An embodiment of the combustion apparatus according to this invention will be described below with reference to FIGS. 1 and 2.

In FIG. 1, a combustion device according to the invention is indicated generally by the numeral 10. For this combustion device 10, for example, air is taken in through an air cleaner of a diesel engine or a gasoline engine, a separate air cleaner, or air is taken in directly from outside or indoors.
The combustion gas from the combustion device 10 is introduced through the air intake pipe 12, and is sent out directly into the room or the like through the combustion gas delivery pipe 13, or sent out to a heat exchanger installed downstream. In the case of sending to a heat exchanger installed downstream, the heat exchanger may be installed in series downstream of the combustion device 10 or installed at the outer periphery of the combustion device 10.

This combustion device 10 includes a combustion tube 11 made of ceramics, a metal outer tube 14 that covers the outer periphery of the combustion tube 11, a metal outer cover plate 5 that seals one end of the combustion tube 11 and the outer tube 14, and a vaporization chamber 7. It is composed of a vaporization chamber forming plate 25 to be formed. A metal combustion gas delivery pipe 13 is provided at the other end of the outer cylinder 14 . The outer cylinder 14 has an air intake port 4, and a metal air intake pipe 12 is attached to the cylindrical portion in which the air intake port 4 is formed. The air intake pipe 12 is attached in the radial direction of the outer cylinder 14, that is, perpendicularly to the outer cylinder 14. In some cases, the air intake pipe may be attached tangentially to the barrel 14.

The inside of the combustion tube 11 is divided into two chambers, namely a vaporization chamber 7 and a combustion chamber 6, by a partition plate 8 having air circulation openings 15 such as a plurality of notched passages on the peripheral edge.
It is divided into. Furthermore, a large number of air introduction holes 17 are formed in the downstream portion of the peripheral wall of the combustion cylinder 11 that constitutes the combustion chamber 6 . An annular air introduction passage 27 is formed between the combustion tube 11 and the outer cylinder 14 through which combustion air circulates, and an air straightening plate 16 is further installed in the annular air introduction passage 27. .

The air straightening plate 16 is composed of an annular air guide plate having a large number of air guide holes 9, and distributes the combustion air introduced from the air intake pipe 12 evenly, that is, uniformly, so that it is distributed evenly in the annular air introduction passage 27. Combustion air is introduced in a uniform state, or combustion air is introduced in an uneven state, and then introduced into the combustion chamber 6 through the air introduction hole 17 to promote the swirling flow formed in the combustion cylinder 11. It can be configured to:

Furthermore, a combustion gas outlet 18 is formed at an end of the combustion chamber 6 on the opposite side from the vaporization chamber 7 so as to be offset in the radial direction. When the combustion gas delivery port 18 is located in a radially biased state, the combustion gas can be efficiently delivered to the heat exchanger. The vaporizer 2 is installed diagonally through the combustion chamber 6 from the downstream corner of the combustion tube 11 toward an opening, that is, a communication hole 19 formed in the center of the partition plate 8. 23 is open to the vaporization chamber 7.

Further, an ignition glow plug 3, which is a heating plug, is installed in the vaporization chamber 7. The vaporizer 2 includes a vaporizing glow plug 2 in a metal vaporizing pipe 20.
9 is built-in. At one end of the vaporizing pipe 20, there is a terminal 2 for supplying current to a resistance wire made of tungsten or the like embedded in a silicon nitride member in a vaporizing glow plug 29 which is a heating plug.
1 is located.

At the other end of the vaporizing pipe 20, the vaporizing pipe 20
A jetting pipe 22 having a smaller diameter is attached, and a fuel jetting port 23 is formed at the tip of the jetting pipe 22. The vaporization pipe 20 includes a fuel supply pipe 2
4, and heat receiving fins 28 are formed on the outer peripheral surface of the vaporizing pipe 20. A jetting pipe 22 extends from the tip of the vaporizing pipe 20, passes through a communication hole 19 formed in the partition plate 8, and furthermore, a fuel jetting port 23 formed at the tip of the jetting pipe 22 extends through a communication hole 19 formed in the partition plate 8. The opening is located near the ignition glow plug 3 installed in the vaporization chamber 7.

Regarding this combustion device 10, the material of the combustion tube 11 constituting the vaporization chamber 7 and the combustion chamber 6 is a dense or porous ceramic member having a low coefficient of thermal expansion. For example, it can be made of a material made of ceramics using cordierite, which has a porous structure and has a small coefficient of thermal expansion. Furthermore, a dense or porous ceramic member with a low coefficient of thermal expansion may be installed on the outer cover plate 5 of the vaporization chamber 7 or the vaporization chamber forming plate 25.

In addition to the above configuration, this combustion device 10 is particularly characterized by the following configuration. That is,
This combustion device 10 has a combustion tube 11 divided into a combustion chamber 6 and a vaporization chamber 7 by a partition plate 8 having an air circulation opening 15, and a blowout pipe 22 of the vaporization device 2, a part of which is located in the combustion chamber 6. is the inner wall surface of the vaporization chamber forming plate 25 that passes through the communication hole 19 of the partition plate 8, the fuel injection port 23 of the injection pipe 22 opens into the vaporization chamber 7, and forms the vaporization chamber 7 facing the fuel injection port 23. is formed into a cup shape, and is further provided with a fuel spray diffusion plate 26 that protrudes into the vaporization chamber 7 toward the fuel injection port 23 and diffuses radially rearward along the fuel injection direction. In particular, the fuel spray diffusion plate 26 has a protrusion 3 in the center that protrudes toward the fuel injection port 23.
2. It has an umbrella shape 31 with a hemispherical cross section.

Furthermore, an air straightening plate 16 is placed in the middle of the annular air introduction passage 27 formed by arranging the outer cylinder 14 around the outer periphery of the combustion tube 11 to introduce air into the combustion chamber 6 inside the combustion tube 11. A large number of air introduction holes 17 are formed in the combustion tube 11 located downstream of the plate 16, and air introduction holes 1 for promoting swirling flow are formed in the combustion tube 11 located upstream of the air straightening plate 16. Combustion air and combustion gas flowing in through the large number of air introduction holes 17 form a swirl in the combustion tube 11 that flows across the combustion chamber 6 and the vaporization chamber 7. The promoting air introduction hole 1 is designed to promote the flow of swirling flow.
The number, position, and inflow angle of the air introduction holes 1 are set for the combustion tube 11.

For example, as shown in FIG. 2, the air introduction hole 1 for promoting swirling flow is formed inside the combustion tube 11 so as to promote the swirling flow formed inside the combustion tube 11. It is formed in an inclined state along the air streamline, that is, the swirling streamline, and is formed on a part of the circumferential surface of the combustion tube 11. However, regarding the swirling flow of combustion air, the air introduction hole 1 of the combustion tube 11
The combustion air introduced into the combustion chamber 6 from 7 is, for example, a symbol A formed on the partition plate 8 (see FIG. 2).
From the air circulation opening 15 in the upper part shown by the vaporization chamber 7
flows into.

Next, the combustion air that has flowed into the vaporization chamber 7, together with the vaporized fuel ejected from the fuel injection port 23, flows through the air circulation opening 15 formed in the partition plate 8 at the lower part indicated by the symbol B (see FIG. 2). It flows into the combustion chamber 6. The swirling flow of combustion air flows in the above-mentioned direction across the vaporization chamber 7 and combustion chamber 6 in the combustion tube 11. However, if the air introduction hole 1 for promoting swirling flow is not formed, the vaporized fuel that has been vaporized once will liquefy, and the liquefied fuel will be carbonized in the lower part of the combustion tube 11, that is, at B (see Fig. 2). The carbon may adhere to the air circulation opening 15 shown in the figure or become a puddle, causing the generation of carbon.

In this combustion device 10, the air introduction holes 1 for promoting swirling flow are formed around 60% of the entire circumference of the combustion tube 11 around the air circulation opening 15 indicated by the symbol B, so that the annular air introduction From the channel 27, fresh air is introduced into the combustion chamber 6 through the air inlet 1 at that location. Therefore, the swirling flow of the mixture of combustion air and vaporized fuel at that location is promoted, and even if carbon is generated, it will be blown away by the promoted swirling flow, or the carbon will be combusted by fresh air. However, phenomena such as carbon puddles or carbon adhesion do not occur at all.

This combustion device 10 is configured as described above, and operates as follows. Note that Figure 2 is the same as Figure 1.
FIG.
1 is drawn to show the relationship between the annular air introduction passage 27 and the air intake pipe 12, although the positional relationship between them is different. This combustion device 10 energizes the resistance wire of the vaporizing glow plug 29 in the vaporizing pipe 20 to heat the vaporizing glow plug 29 and supplies liquid fuel from the fuel supply pipe 24 .

The liquid fuel is vaporized in the vaporization device 2, and the vaporized fuel passes through the space between the vaporization pipe 20 and the vaporization glow plug 29 and reaches the fuel injection port 2 of the injection pipe 22.
Vaporized fuel is injected into the vaporization chamber 7 from the vaporization chamber 3 . At this time, the vaporized fuel injected into the vaporization chamber 7 from the fuel injection port 23 flows so as to diffuse backward in the radial direction along the fuel injection direction, and the ejection streamline of the vaporized fuel is not obstructed and is smooth. form a flow,
There is no possibility that the vaporized fuel is liquefied in the vaporization chamber 7 and mist carbon is generated.

On the other hand, combustion air is fed from the air intake pipe 12, passes through the annular space between the outer cylinder 14 and the combustion cylinder 11, that is, the annular air introduction passage 27, and a part of the combustion air enters the combustion chamber 6 from the air introduction hole 1. Most of the air is blown into the air straightening plate 16 through a large number of air guide holes 9 formed at approximately equal distances (in some cases at different distances).
The air is then blown into the combustion chamber 6 through an air introduction hole 17 formed in the combustion tube 11. That is,
The combustion air blown into the annular air introduction passage 27 from the air intake pipe 12 through the air intake port 4 is
While swirling within the annular air introduction path 27, a portion of the combustion air is blown into the combustion chamber 6 from the air introduction hole 1, and most of the combustion air flows into the annular air downstream from the air guide hole 9 formed in the air baffle plate 16. It is blown into the introduction path 27 in a uniform or non-uniform state.

Next, the combustion air is passed from the annular air introduction passage 27 to the air introduction hole 1 formed downstream of the combustion tube 11.
7 into the combustion chamber 6. Therefore, the combustion air fed into the combustion tube 11, that is, into the combustion chamber 6, uniformly or non-uniformly all around the circumference from the air introduction hole 17 of the combustion tube 11, flows into the combustion tube 11 in an extremely ideal state. blown into the combustion chamber 6,
The combustion air is ideally mixed with the vaporized fuel to generate an air-fuel mixture and form a swirling flow, and the combustion air blown from the air introduction hole 1 promotes the swirling flow formed in the combustion tube 11. be able to. Then, the fuel obtains combustion air and is ignited by the ignition glow plug 3, and furthermore, the vaporized fuel and the combustion air become a mixture and are combusted.

Next, the vaporized fuel is blown into the combustion chamber 6, where it is made into a more homogeneous mixture with the combustion air, and is combusted more completely and vigorously. The vaporized fuel is combusted to become a combustion gas, which is sent out from a combustion gas delivery port 18 formed at the downstream end of the combustion tube 11 through a combustion gas delivery pipe 13 to a heat exchanger (not shown) or the like. When the combustion state in the combustion chamber 6 becomes active, heat of vaporization is received through the vaporization pipe 20 of the vaporization device 2 and the heat receiving fins 28 provided on the vaporization pipe 20. In this state, the energization to the vaporizing glow plug 29 is stopped. Thereafter, the liquid fuel receives combustion heat, in other words, vaporization heat, from the combustion chamber 6 and vaporizes, becomes vaporized fuel, generates a mixture with combustion air, and continues combustion.

In this combustion action, the liquid fuel is heated and vaporized by the vaporizing glow plug 29, and when the vaporized fuel is ejected from the fuel injection port 23, there may be cases where the vaporization of the liquid fuel is incomplete or the vaporization of the liquid fuel is incomplete. 23
When oil droplets are mixed with the vaporized fuel and ejected, it collides with the outer cover plate 5, the combustion cylinder 11, etc., becomes fuel liquid, and flows down the outer cover plate 5 and the partition plate 8 to the bottom. be. In that case, by attaching a ceramic member or the like to the outer cover plate 5 and taking measures such as heat insulation, cooling by the outside air can be prevented, and the collided vaporized fuel and oil droplet fuel can be prevented from being cooled by the outside air. It is possible to prevent the fuel from being deprived of heat, and it is also possible to prevent the vaporized fuel from liquefying and generating mist carbon. In addition, the air introduction hole 1 is formed only in a part of the entire circumference of the combustion tube 11, that is, in a part that does not go against the swirling flow, and is formed at an inclined angle, so that the combustion air is kept in an extremely ideal state. in,
In other words, it is blown into the combustion tube 11 in a state that promotes a swirl flow, and is ideally mixed with the vaporized fuel to generate an air-fuel mixture, thereby promoting combustion.

As mentioned above, the embodiment of the combustion device according to this invention has been described in detail, but it is not necessarily limited to these details. For example, the combustion tube is horizontal type installed almost horizontally, but it can be It goes without saying that it may be installed in any direction, and that it can be changed depending on conditions such as the installation location. Regarding the partition plate that partitions the inside of the combustion cylinder, instead of providing air circulation openings such as a plurality of notched passages on the periphery, it is preferable to have air circulation openings consisting of a plurality of holes in appropriate parts of the partition plate. Alternatively, both the cutout passage and the through hole may be formed as air circulation openings. Additionally, a dense or porous ceramic member with a low coefficient of thermal expansion may be installed on the outer cover plate. Although they are provided in separate directions, it goes without saying that the positional relationship is not limited to this. In addition, in the figure, the air guide holes provided in the annular air guide plate are circular and formed at regular intervals, but the air guide holes are not limited to circular holes, and may include elliptical holes,
They may have various shapes such as elongated holes or square holes, and can be changed in various ways depending on the air inflow speed, air inflow amount, etc., without having to drill holes at equal distance intervals.
Of course, a large number of pores may also be formed. Further, the shape, size, etc. of the air introduction hole shaped into the combustion tube can be similarly changed.

[Effect of idea]

The combustion device according to this invention is constructed as described above and has the following effects. That is, in this combustion device, a combustion tube is divided into a combustion chamber and a vaporization chamber by a partition plate, a fuel injection port of the vaporization device is opened into the vaporization chamber, and the fuel is diffused into the vaporization chamber opposite to the fuel injection port. Since an umbrella-shaped fuel spray diffusion plate with a hemispherical cross section is installed, the liquid fuel is immediately and rapidly vaporized into vaporized fuel by the vaporization device,
The vaporized fuel ejected from the fuel ejection port into the vaporization chamber diffuses and flows radially rearward along the fuel ejection direction, and the ejection stream line is not obstructed, forming a smooth flow. .

In particular, the fuel spray diffusion plate has an umbrella shape with a hemispherical cross section, and the vaporized fuel ejected from the fuel injection port is smoothly diffused from the protruding tip into the umbrella shape along the curved surface in the radial direction. The swirling flow is mixed well with the combustion air that has flowed in from the combustion chamber through the opening of the partition plate to produce an air-fuel mixture, and the vaporized fuel is liquefied in the vaporization chamber to form a mist. No carbon is generated.

Further, the liquid fuel is immediately and rapidly vaporized into vaporized fuel by the vaporizer, and is injected into the vaporization chamber, and combustion air is supplied from the annular air introduction path around the combustion tube to the combustion tube. In addition, by introducing a portion of the combustion air into the vaporization chamber, the vaporized fuel can be ignited very well and reliably. The vaporized fuel and the combustion air can be well mixed in the vaporization chamber, an ideal air-fuel mixture can be generated, and combustion can be promoted, and the combustion gas can be moved vigorously from the combustion chamber to a predetermined direction. It can be delivered to a location, such as a heat exchanger.

Moreover, fresh air is introduced so as to follow the swirling flow, that is, to promote the swirling flow, through the air introduction hole located upstream of the air straightening plate, which is a part where vaporized fuel is likely to liquefy and generate carbon. This can prevent the generation of carbon, blow away the generated carbon, or completely burn the generated carbon immediately with fresh air.

Therefore, according to this combustion device, liquid fuel can be rapidly vaporized, and the vaporized fuel can be rapidly ignited and combusted rapidly and reliably, so that it can rapidly contribute to heating, etc. .

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a combustion device according to this invention, FIG. 2 is a sectional view taken along the line - in FIG. 1, and FIG. 3 is a sectional view showing an example of a combustor according to the prior art. FIG. 4 is a cross-sectional view of another example of a prior art combustor. 1... Air introduction hole, 2... Vaporizer, 6... Combustion chamber, 7... Vaporization chamber, 8... Partition plate, 10... Combustion device, 11... Combustion tube, 15... Air circulation opening ( opening), 17... air introduction hole, 20... vaporization pipe, 23... fuel jet port, 25... vaporization chamber forming plate, 26... fuel spray diffusion plate, 31... umbrella shape,
32... Protrusion.

Claims (1)

[Scope of utility model registration request] A combustion tube formed with a large number of air introduction holes, a partition plate that divides the inside of the combustion tube into a combustion chamber and a vaporization chamber and has an opening that communicates the two chambers, a vaporization pipe is arranged in the combustion chamber, and a vaporizer having a fuel injection port opened in the vaporization chamber; a vaporization chamber forming plate installed in the combustion tube and forming an inner wall surface of the vaporization chamber; and a vaporization chamber forming plate installed on the vaporization chamber forming plate opposite to the fuel injection port. A combustion device characterized by having an umbrella-shaped fuel spray diffusion plate with a hemispherical cross section.