JPS6255563B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a combustion device that vaporizes liquid fuel and burns it as a premixed gas with primary air using a ceramic plate having pores, etc., and reduces the generation of nitrogen oxides in exhaust gas. The purpose is to improve the ignition characteristics while also improving the ignition characteristics.

As shown in FIG. 3, in a conventional combustion device, a fuel supply pipe 3 faces a vaporizer 2 incorporating an electric heater 1, and communicates with a fuel tank 5 via a fuel pump 4. Further, a blower fan 7 is connected via a blower passage 6 . A rectifying chamber 9 is connected to the vaporizer 2 through a mixing passage 8 in the upper part thereof, and a flat ceramic plate 11 having a large number of pores 10 is vertically positioned in front of the rectifying chamber 9. In this case, the vaporizer 2 is heated by the electric heater 1. Along with this, the fuel pump 4 is driven to suck fuel from the fuel tank 5 and the fuel supply pipe 3
The inside of the carburetor is conveyed and fuel is dripped from the tip facing the inside of the carburetor 2. Further, the blower fan 7 is driven to guide combustion air into the carburetor 2 from the blower passage 6. Since the vaporizer 2 is heated, the dropped fuel instantaneously evaporates and generates vaporized gas, which is premixed with air from the blower fan 7 and introduced into the rectifying chamber 9 through the upper mixing passage 8. It will be destroyed. Then, the premixed gas is ejected from the many pores 10 provided on the front surface, ignited by an ignition source (not shown), and the pores 10
It forms a flame. In this case, since the ceramic plate 11 is not heated to a high temperature, the premixed gas tends to condense on the ceramic plate 11 during ignition, and the concentration of the premixed gas is diluted, resulting in unstable ignition and a longer ignition time. It takes a long time, gas ejects from the large number of pores 10, and ignition starts from one part and gradually progresses along the plane of the ceramic plate and burns.
This resulted in incomplete combustion and significantly deteriorated ignition characteristics. Since the ceramic plate 11 does not instantly become red hot, local heating occurs in some areas, and it is difficult to expand the ceramic plate to reduce the flame pore load, making it difficult to suppress the generation of nitrogen oxides. It was hot.

The present invention overcomes the drawbacks of the prior art by providing a means for sufficiently heating the main burner, such as a ceramic plate. Embodiments of the present invention will be described below with reference to FIGS. 1 and 2.

1 and 2, a main vaporization chamber 22 is located near the center of a vaporizer 21 incorporating an electric heater 20.
, an auxiliary vaporization chamber 23 is provided on the outer periphery, a main fuel supply pipe 24 faces the main vaporization chamber 22, an auxiliary fuel supply pipe 25 faces the auxiliary vaporization chamber 23, and each fuel supply pipe is connected to a fuel switching chamber. It is connected to a fuel pump 27 via a valve 26 and communicates with a fuel tank 28. In addition, the combustion air is supplied by making the main ventilation passage 29 face the main vaporization chamber 22 and the auxiliary ventilation passage 30 facing the auxiliary vaporization chamber 23, and each ventilation passage is connected to the ventilation fan 32 via the ventilation switching valve 31. has been done. A rectifying cylinder 34 having a large number of small holes 33 is provided above the main vaporization chamber, and a large number of small holes 3 are provided around the outer circumference of the rectifying cylinder 34.
A flat ceramic plate 3 formed by forming a
Flame hole body 37 formed into a cylindrical shape by combining a plurality of 6 etc.
The main burner is configured with Further, a heating burner having a slit flame hole 38 formed in the upper part of the auxiliary vaporization chamber 23 is disposed near the bottom of the cylindrical flame hole body 37. 39 is a main flame and 40 is an auxiliary flame.

In the above configuration, the vaporizer 21 is heated by the electric heater 20. Next, the fuel pump 27 is driven, and the fuel sucked from the fuel tank 28 is guided to the fuel switching valve 26, and initially the auxiliary fuel supply pipe 25
The fuel is dripped into the auxiliary vaporization chamber 23 and instantaneously becomes vaporized gas by the sufficiently heated vaporization wall. In addition, the blower fan 32 is driven, and the premixed gas with the vaporized gas is initially guided from the auxiliary blower passage 30 to the auxiliary vaporizing chamber 23 at the blower switching valve 31, and is ejected from the slit flame hole 38 of the heating burner and ignited. ignite with a container (not shown). Since the auxiliary flame 40 generated in this slit flame hole 38 is formed near the bottom of the cylindrical flame body 37, the cylindrical flame body 37 is immediately heated. Thereafter, by switching the fuel switching valve 26 and the ventilation switching valve 31, the fuel guided to the main fuel supply pipe 24 enters the main vaporization chamber 22 and instantly becomes vaporized gas. Further, the combustion air guided to the main ventilation passage 29 is sent into the main vaporization chamber 22, and a premixed mixture with vaporized gas is conveyed to the upper part.
3, the flow is evenly rectified and diffused around the outer circumference of the rectifying cylinder 34. Then, the diffused premixed gas is ejected from the pores 35 of the flame hole body 37 forming a cylindrical shape formed by combining the flat ceramic plates 36. During this switching, the premixed gas in the auxiliary vaporization chamber 23 is not consumed immediately, but the slit 38 gradually changes the premixed gas to the auxiliary flame 4.
0 becomes smaller. For this reason, it becomes an ignition source for the premixture ejected from the pores 35 of the flame hole body 37,
A main flame 39 is instantaneously formed in the pores 35 on the ceramic plate.

At this time, since the cylindrical flame hole body 37 made up of a plurality of ceramic plates 36 is in a sufficiently heated state, a flame is formed uniformly over the entire surface of the pores 35. The ceramic plate surface becomes red hot and generates radiant heat.

As described above, by forming a flame after heating the main burner such as a ceramic plate with a heating burner, it is possible to form a flame uniformly over the entire surface of the flame body that makes up the pores, and ignition is also carried out smoothly. Therefore, combustion characteristics at startup are improved, and the uniform flame eliminates local heating, making it possible to control the generation of nitrogen oxides. In addition, by making the main burner, such as a ceramic plate, large, the entire periphery of the flame hole becomes red-hot, and radiant heat is dissipated all around, making it possible to further improve the heating effect and further control the generation of nitrogen oxides. be.

[Brief explanation of the drawing]

FIG. 1 is a front cross-sectional view showing an embodiment of the combustion device of the present invention, FIG. 2 is a plan cross-sectional view of the combustion device, and FIG. 3 is a cross-sectional view of a conventional combustion device. 21... vaporizer, 22... main vaporization chamber, 23...
Auxiliary vaporization chamber, 24...Main fuel supply pipe, 25...Auxiliary fuel supply pipe, 26...Fuel switching valve, 27...Fuel pump, 29...Main ventilation passage, 30...Auxiliary ventilation passage, 31... Air blowing switching valve, 32... Blowing fan, 35... Fine hole, 37... Flame hole body (main burner), 38... Slit flame hole (heating burner).

Claims (1)

[Claims] 1. A carburetor incorporating an electric heater, a main vaporization chamber formed near the center of this vaporizer, an auxiliary vaporization chamber formed in a ring shape around the periphery of the carburetor, and a main fuel supply opening into the main vaporization chamber. A pipe and a main ventilation passage, an auxiliary fuel supply pipe and an auxiliary ventilation passage that open to the auxiliary vaporization chamber, and a fuel switching valve that guides liquid fuel supplied from the fuel pump to either the main fuel supply pipe or the auxiliary fuel supply pipe. , a ventilation switching valve that guides the combustion air supplied from the ventilation fan to either the main ventilation passage or the auxiliary ventilation passage, a main burner consisting of a ceramic plate, etc. that burns the premixed gas generated in the main vaporization chamber, and an auxiliary combustion chamber. A heating burner consisting of a slit flame hole or the like for burning the premixed gas generated in the vaporization chamber, the cylindrical main burner, and the ring-shaped heating burner are arranged so that the respective premixed gas ejection directions are perpendicular to each other. The combustion device also includes a control means that supplies fuel and combustion air to the auxiliary vaporization chamber at the time of ignition, and switches the supply to the main vaporization chamber after a certain period of time has elapsed.