JP2566693B2 - Air-fuel ratio controller for oil fan heater and control method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil-fuel heater air-fuel ratio control system for controlling fuel supply and combustion air supply by separate electromagnetic control, and a control method therefor, and more particularly to a fuel for an oil fan heater. An air-fuel ratio control system for an oil fan heater capable of sensing the air pressure supplied with respect to the discharge amount and controlling the rotation speed of the burner motor so as to obtain an optimum air-fuel ratio by a detection signal based on the change in the air pressure, and It relates to a control method.

[0002]

2. Description of the Related Art In a conventional air-fuel ratio control system for an oil fan heater, when a certain amount of petroleum fuel is supplied to the oil fan heater, a burner rotation speed is preset so that a certain amount of combustion air is supplied. Is set in advance, and the burner motor is driven by the set rotational speed to supply the combustion air to the burner.

However, in the air-fuel ratio control system for an oil fan heater thus configured, if the rotation speed of the burner motor is set in advance, the amount of oxygen differs depending on the temperature difference of the air supplied to the burner. The optimum air-fuel ratio can be maintained if the mechanical mechanism and burner motor characteristics are good, but if the mechanical mechanism of the oil fan heater and burner motor characteristics or the temperature characteristics of the surrounding environment change, the optimum air-fuel ratio can be maintained. Could not mix. Therefore, the fuel is incompletely burned to increase fuel consumption, the combustion efficiency of the oil fan heater cannot be improved, and heavy soot is discharged.

[0004]

Therefore, the present invention has been made in view of the above-mentioned various problems, and an object of the present invention is to sense the air pressure supplied so that the fuel is completely burned, An object of the present invention is to provide an air-fuel ratio control system for an oil fan heater and a control method therefor capable of controlling the rotation speed of a burner motor by changing the air pressure.

[0005]

In order to achieve the above object, the air-fuel ratio control system for an oil fan heater according to the present invention is an air-fuel ratio for an oil fan heater provided with a fuel supply means and an air supply means for combustion. In the control system, an air pressure sensing means for sensing the air pressure supplied to the burner by the rotation of the burner motor is provided in the air passage between the burner motor and the burner.

Further, according to the air-fuel ratio control method for an oil fan heater of the present invention, the air pressure of the burner motor is measured by an air pressure sensing circuit, and the rotation speed of the burner motor is reduced when the measured value is a preset value or more. The air-fuel ratio is optimally controlled by increasing the number of rotations of the burner motor when it is below a certain value.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a circuit block diagram of an air-fuel ratio control system for an oil fan heater according to an embodiment of the present invention, FIG. 2 is an output voltage waveform diagram with respect to a change in air pressure of a burner motor, and FIG. 6 is a flowchart showing a procedure for controlling a fuel ratio.

In FIG. 1, reference numeral 1 denotes a microcomputer (hereinafter referred to as a microcomputer) for controlling all fuel combustion operations.
2 is a constant power supply unit for supplying operating power, 3 is a key operation unit for instructing a user's command, 4 is a display unit showing the operating state of the oil fan heater, and 5 is in the burner. Is a temperature sensing unit that senses the temperature and the room temperature, and 6 is a flame sensing unit that senses a flame due to combustion of fuel.

In the figure, 8 is a heater driving section for heating the heater 7 to heat the burner, 10 is an electromagnetic pump driving section for driving the electromagnetic pump 9 to supply fuel to a burner (not shown), 15 Is a fan motor drive unit for driving the fan motor 13 to discharge the heated air heated by the burner into the room, and 17 is the fan motor 1
3 is a fan motor rotation speed sensing unit that senses the rotation speed of 3. 16 is a burner motor 1 for supplying combustion air.
4, a bar motor drive unit for driving 4, and 20 is provided in an air passage between the burner motor 14 and a burner (not shown), and constitutes an air pressure sensing means for sensing the air pressure supplied to the burner by the rotation of the burner motor 14. This is a pneumatic pressure sensing circuit.

The air pressure sensing circuit 20 includes an amplifier 22, resistors R5 and R6 connected to the non-inverting terminal (+) of the amplifier 22, one end of which is connected to the inverting input terminal (-) and the other end thereof. A constant current circuit 21 composed of a resistor R7 connected to ground; a bridge circuit 23 composed of resistors R1 to R4 for shaping the output current IN of the constant current circuit 21;
It is composed of an amplifier circuit 24 for amplifying the output voltage VS of the bridge circuit 23.

In the air pressure sensing circuit 20 of the burner motor 14 thus constructed, when an electric signal from a pressure sensor provided in the air passage between the burner motor 14 and the burner is input to the input terminal of the resistor R5 of the constant current circuit 21. The amplifier 22 subtracts the difference from the reference voltage on the inverting input terminal side, and the output current IN corresponding to this voltage is generated. Then, when the output current IN output from the amplifier 22 of the constant current circuit 21 is supplied to the bridge circuit 23, the output voltage VS is calculated by the following formula [1] according to the increase or decrease of the pressure of the air supplied by the burner motor 14. expressed.

[0013]

[Equation 1]

Here, IN indicates a current value determined by VR / R7 which is always output by the constant current circuit 21. In this way, the bridge circuit 2 is formed by shaping the current drawn from the constant current circuit by the bridge circuit.
The fine pneumatic output voltage VS in FIG.
4, the output voltage Vout linearly changes due to the change in the air pressure of the burner motor 14, and this output voltage Vout is input to the input terminal IN6 of the microcomputer. That is, the air pressure sensing circuit 20 of the burner motor 14
Output Vout of the microcomputer 1 is input to the input terminal IN6 of the microcomputer 1, and when the air pressure of the burner motor 14 is equal to or higher than a constant value M preset in the microcomputer 1, the output terminal OUT5 of the microcomputer 1 to the burner motor drive unit 16 is applied to the burner motor. A control signal is output so as to decrease the rotation speed of the burner motor 14. Conversely, when the air pressure of the burner motor 14 is below a certain value, the rotation speed of the burner motor 14 is increased from the output terminal OUT5 of the microcomputer 1 to the burner motor drive unit 16. A control signal is output to.

In the petroleum fan heater thus constructed, when the key operation unit 3 is operated to input an operation command to the input terminal IN2 of the microcomputer 1 while the constant power supply unit 2 supplies the operation power, the microcomputer 1 Outputs a signal to the output terminal OUT1 to indicate to the display unit 4 that the oil fan heater is operating, and outputs a signal to the output terminal OUT2 to drive the heater driving unit 8 to heat the heater 7. , A burner (not shown) is heated. At this time, the temperature sensing unit 5 senses the temperature of the burner to detect the input terminal IN of the microcomputer 1.
A signal relating to the sensed temperature is input to 4.

When the burner rises above a certain temperature in such a state, the microcomputer 1 outputs a control signal for driving the electromagnetic pump 9 to the output terminal OUT3 so that the electromagnetic pump 9 is driven. The electromagnetic pump drive unit 10 drives the electromagnetic pump 9 by this control signal to inject fuel (petroleum) into the burner and drive an igniter (not shown) to ignite the fuel injected from the burner. When the petroleum fuel is ignited and combustion starts in this way, the microcomputer 1 outputs the output terminal O
A fan motor drive control signal is output to drive the fan motor 13 to the UT 4, and the fan motor 13 is driven.

As a result, the air heated by burning the fuel is discharged into the room by driving the fan motor 13. At this time, the microcomputer 1 outputs a control signal to the burner motor drive unit 16 through the output terminal OUT5 to output the burner motor 14
To supply combustion air to the burner. Further, the fan motor rotation speed detection unit 17 detects the rotation speed of the fan motor 13 and outputs the signal to the input terminal IN7 of the microcomputer 1.
To enter. The air pressure sensing circuit 20 of the burner motor 14 senses the air pressure of the burner motor 14 and inputs the signal to the input terminal IN6 of the microcomputer 1. Then, the flame sensing unit 6 measures the flame sensing voltage due to the combustion of the fuel and inputs the signal to the input terminal IN5 of the microcomputer 1. This is because the flame temperature of the burner changes depending on the supply amount of the combustion air, and the air pressure of the burner motor changes accordingly, so the flame temperature of the burner also affects the optimum air-fuel ratio control.

Therefore, the optimum air-fuel ratio control system for the oil fan heater according to the present invention senses the air pressure of the burner motor 14 by the air pressure sensing circuit 20 to determine whether or not the air pressure is equal to or higher than a constant value M. In some cases, the pressure of the combustion air is controlled in consideration of the flame detection voltage detected by the flame detection unit 6, and the optimum air-fuel ratio is controlled so that the combustion is performed in the optimum combustion state. There is. It goes without saying that the display unit 4 can be configured not only to show the room temperature, the set temperature, the operating state of the key operating unit 3 and the like, but also the driving states of the electromagnetic pump 9, the fan motor 13 and the burner motor 14.

FIG. 3 is a flow chart showing the procedure of the air-fuel ratio control system for the oil fan motor of the present invention. In the figure, S indicates a step.

First, when a constant power source is input from the constant power source unit 2 to the input terminal IN1 of the microcomputer 1 and a power switch is turned on by operating a switch (not shown) of the oil fan heater, initialization is set in step S100. . Next, in step S101, the key function is performed by operating the key operation unit 3 to instruct a user's command. Next, in step S102, the display by the key function, that is, the display according to the user's instruction is shown on the display unit 4. Next, in step S103, it is determined whether the operation switch of the key operation unit 3 is turned on, and Y
In the case of es, the process proceeds to step S104 to output a signal to the output terminal OUT2 of the microcomputer 1 to drive the heater driving unit 8 to heat the heater 7 and heat the burner. Next, in step S105, the temperature sensing unit 5 determines whether the heat generation temperature of the heater 7 is equal to or higher than a certain temperature (X). At this time, if the temperature is equal to or higher than the certain temperature X, that is, if Yes, the process proceeds to step S106 to drive an igniter (not shown) to ignite, and then the process proceeds to step S107 to compare the indoor temperature and the set temperature to determine the heat generation stage. To do. On the other hand, if the operation switch is not turned on in step S103, or if the heater temperature is equal to or lower than the constant temperature X in step S105, step S10.
After returning to 0, the operation from step S100 onward is repeated.

Next, in step S108, the electromagnetic pump 9, the fan motor 13 and the burner motor 14 are driven. Then, the combustion fuel is supplied by the electromagnetic pump 9,
The air heated by the combustion of the combustion fuel by the fan motor 13 is discharged into the room, and the burner motor 14 ignites and burns the fuel while supplying the combustion air for the fuel to the burner.

When the fuel burns in this way, step S
After proceeding to 109 and checking the current air pressure H of the burner motor 14 by the air pressure sensing circuit 20, step S
The routine proceeds to 110, where it is determined whether or not the current air pressure H is larger than a constant value M preset in the microcomputer 1. Then, when the current air pressure H is higher than the constant value M, that is, in the case of Yes, a signal is output to the output terminal OUT5 of the microcomputer 1 so as to reduce the rotation speed of the burner motor 14, and then the process proceeds to step S109. Return to step S109
The following operation is repeated.

On the other hand, in step S110, the current air pressure H
Is smaller than the constant value M, that is, No, the process proceeds to step S112, a signal is output to the output terminal OUT5 of the microcomputer 1 so as to increase the number of revolutions of the burner motor 14, and the process returns to step S109 to perform the operations of step S109 and subsequent steps. Repeat.

When the current air pressure H is compared with a constant value M to increase or decrease the number of revolutions of the burner motor, the value of the flame sensing voltage sensed by the flame sensing unit 6 is also taken into consideration to rotate the burner motor. By adjusting the increase and decrease of the number, the supply amount of combustion air can be controlled. For example, when it is determined that the flame temperature has risen due to the flame detection voltage, the combustion air has been excessively supplied, and therefore the burner motor rotation speed determined by comparing the air pressure H with the constant value M The amount of air supplied can be reduced by performing correction so as to reduce the number of revolutions of the burner motor, and more appropriate fine control can be performed.

[0025]

As described above, according to the air-fuel ratio control device for a petroleum fan heater and its control method of the present invention, by combining a constant current circuit, a bridge circuit and an amplifying circuit as the structure of the air pressure sensing means of the burner motor, It is possible to detect various pressure differences and obtain measurement results with less error. Therefore, the air-fuel ratio of the oil fan heater is optimally controlled by sensing such a fine air pressure, and the problem of incomplete combustion can be solved. In addition, the fuel consumption can be reduced and the combustion efficiency of the oil fan heater can be improved without the problem of soot and smoke. Furthermore, by sensing the air pressure of the burner motor to control the air-fuel ratio, and at the same time sensing the flame of the burner to control the air-fuel ratio, it is possible to change the mechanism of the oil fan heater and the characteristics of the burner motor or the temperature characteristics of the ambient environment. Also has an excellent effect that the air-fuel ratio can be appropriately controlled to improve the combustion efficiency.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of an air-fuel ratio control system for an oil fan heater according to an embodiment of the present invention.

FIG. 2 is an output voltage waveform diagram with respect to a change in air pressure of the burner motor.

FIG. 3 is a flowchart showing a procedure for controlling an air-fuel ratio of an oil fan heater.

[Explanation of symbols]

 1 Microcomputer (microcomputer) 2 Constant power supply part 3 Key operation part 4 Display part 5 Temperature detector 6 Flame detection part 7 Heater 9 Electromagnetic pump 13 Fan heater 14 Burner motor 17 Fan motor rotation speed detection part 20 Air pressure detection circuit 21 Constant current circuit 24 amplifier circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-41949 (JP, A) JP-A-3-291411 (JP, A) Actually opened 1-129561 (JP, U) Actually opened 62- 148856 (JP, U)

Claims (3)

(57) [Claims] 1. An air-fuel ratio control device for a petroleum fan heater comprising a fuel supply means and an air supply means for combustion, comprising:
An air-fuel ratio control system for an oil fan heater, comprising air pressure sensing means for sensing air pressure supplied to the burner by rotation of the burner motor in an air passage between the burner motor and the burner, wherein the air pressure sensing means comprises: A pressure sensor provided in the air passage between the burner motor and the burner, a constant current circuit that outputs a constant current according to the electric signal of the pressure sensor, and a constant current output by the constant current circuit An air-fuel ratio control device for an oil fan heater, comprising: a bridge circuit for shaping; and an amplifier circuit for amplifying an output voltage of the bridge circuit. 2. The constant current circuit comprises an amplifier, two resistors connected to the non-inverting input terminal of the amplifier, and a resistor having one end connected to the inverting input terminal of the amplifier and the other end grounded. The air-fuel ratio control device for an oil fan heater according to claim 1, which is characterized in that. 3. The air pressure in the air passage between the burner motor and the burner is measured by an air pressure sensing circuit, and when the measured value is equal to or higher than a preset constant value, the rotational speed of the burner motor is reduced to a predetermined value or less. Is a method for controlling the air-fuel ratio of the oil fan heater by increasing the rotation speed of the burner motor to optimally control the air-fuel ratio.Furthermore, the flame temperature due to the combustion of the fuel is measured as the flame sensing voltage by the flame sensing unit. , Determining the air supply amount to the burner motor based on the measured value, further reducing the rotation speed of the burner motor determined by comparing the measured value of the air pressure with a preset constant value according to the determined air supply amount, or An air-fuel ratio control method for an oil fan heater, comprising the step of increasing.