JPS63105319A - Combustion control apparatus - Google Patents

Abstract

PURPOSE:To enable a stable combustion state to be maintained by a method wherein a part of carburetor unit is provided with a temperature control means for controlling a temperature of the carburetor unit and a heating amount sensing means, and either air or fuel supplying volume is controlled in response to an output from the heating amount sensing means. CONSTITUTION:A heat receiving part 8 is projected to be heated by a flame generated at a combustion part 1 and a combustion heat is transmitted to a carburetor unit 5. A heating amount sensing means 9 arranged in the carburetor unit 5 may calculate an input wattage in reference to an electrical current value and a voltage value of a heater 6. A temperature sensing means 10 is composed of a thermocouple or thermistor, measures a temperature of air supplied from a blower 4 and outputs it to a temperature sensing part 11. An amount of fuel supplied from a fuel pump 3 is set in response to a load, and an output corresponding to its supplying amount is outputted to a combustion amount input part 12. A calculation and comparing means 13 may compare a comparison value with a value stored in advance in response to a value inputted from a heating amount sensing part 9, a temperature sensing part 11 and a combustion amount input part 12 and then outputs it to the an amount of air controlling part 14. The amount of air controlling part 14 may control the number of revolution of the blower 4 in response to an input from the calculation and comparing part 13.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an air-fuel ratio control device for combustion equipment that uses fuel such as gas or oil.

Conventional technology When burning gas or oil as fuel, stable combustion can be maintained by preventing backfire, misfire, or incomplete combustion by supplying the fuel and air at an optimal ratio. This ratio of the amount of fuel and air is called the air-fuel ratio, and conventional methods have been devised to detect the combustion state and control the amount of fuel or air so as to always maintain an optimal air-fuel ratio.

An air-fuel ratio control system for oil-burning equipment is described, for example, in Japanese Patent Laid-Open No. 61-24917. This is a configuration in which the flame ion current of the flame is detected by a flame iron inserted into the flame, and the drive frequency of the fuel supply pump is adjusted to optimize the air-fuel ratio by utilizing the fact that this ion current changes depending on the air-fuel ratio. It is. FIG. 3 shows an example of the flame ion current value ry. The horizontal axis is the primary air ratio μ, and here the air-fuel ratio will be explained in terms of the primary air ratio μ.

Typical burner input range (5ooo~1000kc
al/h), the flame ion current value If is approximately μ=
It has a distribution with a peak at 0.8 to 0.9.

Therefore, by adjusting the pump drive frequency, the flame ion current value I
By determining the fuel supply amount so that f becomes the maximum value, air-fuel ratio control is performed to maintain a stable combustion state.

Problems to be Solved by the Invention In the conventional example described above, a burner configured to maintain the most stable combustion state at μ=0.8 to 0.9 was used.
There is also a burner (hereinafter referred to as a full-combustion burner) that is configured to maintain the most stable combustion state around μ=1.6. Full-primary combustion burners generally have low flame temperatures and extremely low levels of nitrogen oxides (Nox), which are harmful components in exhaust gas, and are highly effective burner configurations for clean combustion. Are known.

However, the conventional air-fuel ratio control means as described above determines the fuel supply amount so that the flame ion current value Xf becomes the maximum value, so it is adjusted to μ = 0.8 to 0.9, and μ = 1
．． If a stable combustion state cannot be maintained near 5 and the input to the burner is small and the combustion amount is small, Ij
The problem is that the value is small and the amount of change is even smaller, making detection difficult.

The present invention aims to solve such conventional problems, and aims to maintain a stable combustion state by adjusting μ to around 1.6 in a full-primary combustion burner.

Means for Solving the Problems In order to solve the above problems, the combustion control device of the present invention includes means for supplying fuel and air, a vaporizer having a heating means connected to the supply means, and a vaporizer for the vaporizer. a combustion section that communicates with at least a portion of the vaporizer, a heat receiving section that is located close to the combustion section that forms a flame, and a temperature control section that detects the temperature of the vaporizer and controls heating of the heating section. and combustion control, comprising heating amount detection means for detecting the amount of heat added to the heating means, and increasing or decreasing the supply amount of the air or the fuel supplying means according to the output of the heating amount detection means. It is a structure that has the following.

Effects According to the present invention, with the above-described configuration, the amount of heat transferred from the combustion flame to the heat receiving section changes due to a change in the air ratio. Since the amount of heat received by the carburetor from the combustion flame can be measured by the heating amount detection means, the air-fuel ratio can be arbitrarily adjusted by increasing or decreasing the supply amount of the means for supplying air or fuel to a preset value. It can be set to maintain a stable combustion state at an air-fuel ratio of around 1.5 μm.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the embodiment, an indoor open combustion hot air heater (fan heater) using an oil vaporization burner will be described as an example. FIG. 1 shows a system block diagram of the present invention. Reference numeral 1 denotes a full-primary combustion burner in which a flame hole is formed with a wire mesh 1c on the outside of a simple 1b made of a perforation plate having a large number of Ω small holes 1& in the combustion part, and is supplied from a fuel tank 2 by a fuel pump 3. The fuel and the air supplied by the blower 4 are supplied to the carburetor 5. The vaporizer 6 is maintained at a constant high temperature by controlling a heater 6 and a temperature detection unit 7 such as a thermistor, and the supplied fuel is vaporized, mixed with air, and supplied to the combustion section 1 as a mixed gas, where it is combusted. . Reference numeral 8 denotes a heat-receiving portion of the vaporizer 6 that protrudes near the combustion portion 1 so as to be heated by the flame generated in the combustion portion 1, and transfers combustion heat to the vaporizer 6. Reference numeral 9 denotes a heating amount detector section of the heater 6 provided in the vaporizer, which calculates the input wattage based on the current value and voltage value of the heater 6. Reference numeral 10 denotes a temperature detecting means for detecting temperature, which is composed of a thermocouple or a thermistor, and measures the temperature of the air supplied from the blower 4 and outputs it to the temperature detecting section 11. fuel pump 3
The amount of fuel supplied is set according to the load, and an output corresponding to the supplied amount is output to the combustion amount input section 12. 1
3 is an arithmetic comparison section, which includes a heating amount detection section 9 and a temperature detection section 11.
The comparison value is compared with a previously stored value according to the value inputted from the combustion amount input section 12, and is output to the air amount control section 14. The air amount control section 14 controls the number of revolutions of the blower 40 in accordance with the input from the arithmetic comparison section 13 to increase or decrease the air amount.

FIG. 2 shows the electrical input amount (hereinafter input W
). The input W increases as the primary air ratio μ increases and as the combustion amount increases. This is because as the combustion amount and the primary air ratio μ increase, the amount of combustion gas increases, and the ejection speed from the flame hole becomes faster, and the combustion speed slows down due to an increase in the primary air ratio μ. This is because the temperature of the heat receiving part 8 becomes lower because it is formed at a more distant position. The amount of heat transferred from the heat receiving section 8 to the vaporizer 5 is determined by the distance of the heat receiving section 8 from the flame and the shape of the heat receiving section 8. In the case of the same heat receiving part 8, the influence of fuel evaporation and temperature change in the air is small and is determined only by the change in combustion speed due to the amount of air and the ejection speed from the flame hole. Therefore, -
The larger the secondary air ratio μ and the larger the combustion amount, the farther the flame is from the heat receiving section 8 and the larger the input W to the heater 6 becomes.

The heat from the vaporizer 6 is radiated to the air flowing inside and to the outside of the vaporizer 5, and the amount of heat radiated to the outside is always constant because the temperature of the vaporizer 6 is constant. As the amount of air increases, the amount of heat radiated to the air increases, and at the same time, the amount of heat transferred from the heat receiving section 8 decreases.

The amount of heat transfer changes in correlation with the amount of air, and since the input W=the amount of heat radiation−the amount of heat transfer, the amount of increase in human power W correlates with the amount of change in the air. The input W is detected by the heating amount detection section 9. The heating amount detection section 9 sequentially measures the electric current and voltage flowing through the heater, and outputs it to the calculation section 13. The arithmetic comparison unit 13 is made to store in advance the values of the primary air pressure μ and the input W when the combustion amount and the air ratio μ are changed. Burning amount input section 12! By inputting the combustion amount, the primary air ratio μ can be determined by comparing it with the above value.

Then, it is compared with the set primary air ratio μ, and if the primary air ratio μ is different from the set value, the air control unit 14 adjusts the rotation speed of the blower 4 by increasing or decreasing it. Therefore, since the air ratio can be freely set to an optimum value, it can be set even in the entire range such as the primary air ratio μ=1.6. In addition, while the flame ion current is affected by the oxygen concentration in the room and gases such as cigarettes, the present invention, which measures the amount of heat due to the temperature rise of the supplied air,
Since the temperature rise is correlated with the air mass flow rate, it is not affected by the above effects. In this embodiment, a full-primary combustion burner has been described, but in the case of a partially premixed combustion burner, the primary air ratio μ can be detected and controlled in the same way, and room temperature or the like may be substituted for the input temperature.

Moreover, if the temperature of the supplied air is outputted to the temperature detection section 11 by the temperature detection means 10 and the amount of heat radiated to the air from the vaporizer 6 is corrected by the arithmetic comparison section 13, even more advanced control becomes possible.

In the above configuration, the blower 4 is adjusted so that the value corresponding to the set primary air ratio μ and the combustion amount is the same as the first value, and the amount of supplied air is controlled. Keep the ratio constant (for example μ = 1.5) to maintain good combustion conditions. Although this example has been explained using an oil fan heater, the same effect can be achieved even with combustion devices other than fan heaters or gas combustion, and instead of a vaporizer that maintains a constant temperature, a heater and a means for detecting the heating temperature are used. The same applies even if it is provided.

Furthermore, if a part of the carburetor faces the combustion chamber and the combustion heat is fed back to the carburetor, the temperature of the flame decreases as the -order air ratio μ increases, and the flame moves away from the flame hole, so the input W and μ The change in will increase more. Furthermore, when the flame hole is deformed or there is an abnormality such as a blockage of the combustion section outlet, the temperature of the vaporizer rises, increasing the amount of air and preventing danger.

In addition, in this example, the primary air ratio μ was optimally adjusted by increasing or decreasing the amount of air, but the same result is obtained if the amount of fuel supplied is increased or decreased, and the same is true when the fuel is gas. .

Effects of the Invention As described above, the combustion control device of the present invention provides the following effects.

(1) Since the air-fuel ratio can be automatically set to the optimal point, a stable combustion state can be maintained at all times without the need for manual adjustment.

(2) Since the air-fuel ratio can be set according to the amount of combustion, it can be varied with good combustion, and the range of variable combustion amount can be expanded, making it possible to control the amount of combustion according to the load.

(3) Since it can be adjusted by μ=1.4 to 1.8, NOx
It can be applied to combustion control in full combustion burners with low combustion.

4) Unlike flame ion current, the temperature is controlled according to the mass flow rate value of the supplied air, regardless of the combustion state, so accurate air ratio control is possible without being affected by room temperature or combustion state. .

(6) Since the supply air means is controlled according to the input amount of the carburetor, the response speed is fast, and even if the air filter is partially clogged with dust etc., even if the air ratio shifts, it can be adjusted instantly.

[Brief explanation of the drawing]

Fig. 1 is a control block diagram of a combustion control device according to an embodiment of the present invention, Fig. 2 is a characteristic diagram of the primary air ratio and heating input amount of the carburetor, and Fig. 3 is a characteristic diagram of a conventional air-fuel ratio control method. It is. 1... Combustion part, 3... Fuel pump, 4
...Blower, 5... Carburizer, 6...
... Heating heater, 7. River... Temperature detection section, 8...
...Heat receiving part, 9... Heating amount detection part, 12...
... Combustion l input section, 13... Comparison calculation section,
14... Air amount control section. Name of agent: Patent attorney Toshio Nakao and 1 other person/-
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Hi117 --- Kahiryo Garadego

Claims (2)

[Claims] (1) A vaporizer having a means for supplying fuel and air, a heating means connected to the supply means, a combustion section communicating with the vaporizer, and at least a part of the vaporizer located close to the combustion section. a heat receiving section located at a temperature of 100 m, a temperature control means for detecting the temperature of the vaporizer and controlling heating of the heating means, and a heating amount detecting means for detecting the amount of heat applied by the heating means, the heating amount detecting means A combustion control device that increases or decreases the supply amount of the means for supplying the air or the fuel according to the output of the combustion control device. (2) A patent that includes a temperature detection means provided in the means for supplying fuel and air, and the supply amount of the air or fuel supply means is increased or decreased according to the output of the temperature detection means and the output of the heating amount detection means. A combustion control device according to claim 1.