JPH10103660A - Method and equipment for controlling combustion of burner by oxygen sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable control of an air ratio and detection of the concentration of an unburned component in exhaust by a single oxygen sensor, by checking the concentration of the unburned component in the exhaust of combustion of a burner on the basis of an output current of the oxygen sensor having a solid electrolyte, in a state wherein a voltage for detecting an unburned state is applied on the oxygen sensor. SOLUTION: When a voltage is applied on a solid electrolyte 21 and a current is made to flow forcedly under the condition of a temperature of a prescribed value (e.g. 650 deg.C) or above in a lean area of fuel gas, migration of O<2-> ions from a cathode to the anode side through the solid electrolyte 21 occurs and a current value is detected by a current detector 3. An applied voltage switchover means 2 switches an applied voltage of an oxygen sensor 20 having the solid electrolyte 21 between a voltage for controlling an air ratio and a voltage for detecting an unburned state in the vicinity of 0V. In the state wherein the applied voltage is the voltage for detecting the unburned state, the concentration of an unburned component in exhaust is checked on the basis of the amplitude of a minus output current of the oxygen sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a burner combustion control method and apparatus using an oxygen sensor.

[0002]

2. Description of the Related Art The applicant of the present invention has proposed a method and an apparatus for controlling combustion of a burner using an oxygen sensor in Japanese Patent Application No. 8-127158. There, an oxygen sensor having a zirconia solid electrolyte at the site that contacts the exhaust (for example,
An in-vehicle oxygen sensor) was installed, the oxygen concentration in the exhaust gas was detected based on the output current value of the oxygen sensor, and the air ratio was controlled so as to reach a predetermined oxygen concentration.

[0003]

However, the conventional combustion control method and apparatus using an oxygen sensor have the following problems to be solved. That is, in the conventional usage of the oxygen sensor, the oxygen sensor detects only the oxygen concentration in the exhaust gas and detects the concentration of unburned components such as carbon monoxide (CO) and hydrocarbons (HC) in the exhaust gas. It is not possible. Therefore, even if the air ratio control is performed using the oxygen sensor so that the oxygen concentration in the exhaust gas becomes a predetermined value, the exhaust gas may contain unburned components in excess of the allowable amount. In order to prevent the emission of unburned components, a system for detecting the concentration of unburned components in the exhaust gas must be provided in addition to the oxygen sensor, and such equipment costs are required. An object of the present invention is to provide a burner combustion control method and apparatus capable of performing air ratio control and detecting unburned component concentration in exhaust gas using a single oxygen sensor.

[0004]

The present invention to achieve the above object is as follows. (1) The applied voltage of the oxygen sensor having the solid electrolyte is set to 0
A burner combustion control method using an oxygen sensor, comprising the step of checking the concentration of unburned components in exhaust gas from burner combustion based on the output current of the oxygen sensor when the unburned detection voltage is near V. (2) The step of switching the applied voltage of the oxygen sensor having the solid electrolyte between the air ratio control voltage and the unburned detection voltage near 0 V, and the period during which the applied voltage is switched to the air ratio control voltage Performing an air ratio control and checking the unburned component concentration while the applied voltage is switched to the unburned detection voltage. (3) When the organic substance due to the combustion reaction adheres to the oxygen sensor and the output current value changes from the initial value, the heater of the oxygen sensor is energized in a clean state to burn the adhered organic substance (1) or (2). A burner combustion control method using an oxygen sensor. (4) An oxygen sensor having a solid electrolyte, an applied voltage switching means for switching an applied voltage of the oxygen sensor between an air ratio control voltage and an unburned detection voltage near 0 V, and an applied voltage being an unburned detection voltage And an unburned component concentration check means for checking the unburned component concentration in the exhaust gas based on the magnitude of the negative output current of the oxygen sensor in the state described above. (5) An oxygen sensor having a solid electrolyte, an applied voltage switching means for switching an applied voltage of the oxygen sensor between an air ratio control voltage and an unburned detection voltage near 0 V, and an applied voltage being an unburned detection voltage The unburned component concentration check means for checking the unburned component concentration in the exhaust gas based on the magnitude of the negative output current of the oxygen sensor when the air pressure is in the range, and the air ratio control is executed when the applied voltage is at the air ratio control voltage And a combustion control device for a burner using an oxygen sensor. (6) The burner combustion control according to (4) or (5), further comprising an oxygen sensor regeneration executing means for judging whether or not an abnormality has occurred in the oxygen sensor output, and executing the oxygen sensor regeneration if the abnormality has occurred. apparatus.

In the air ratio control using a conventional oxygen sensor, a predetermined applied voltage is always applied to the oxygen sensor having a zirconia solid electrolyte. However, the present inventors have found that when the applied voltage of the oxygen sensor is set to around 0 V, the output current of the oxygen sensor changes according to the amount of unburned components in the exhaust gas. The present invention proposes a method and an apparatus for detecting the amount of unburned components in exhaust gas by using this phenomenon to control burner combustion. In the method of (1) and the apparatus of (4), the same oxygen sensor used for air ratio control is used, the applied voltage is set to around 0 V, and the unburned components in the exhaust gas based on the output current of the oxygen sensor. Detect the amount of fuel and check for unburned components in exhaust gas. Therefore, no special unburned component sensor is required. In the method (2) and the device (5), when the air ratio control is performed by the oxygen sensor, the applied voltage of the oxygen sensor is switched to around 0 V at predetermined time intervals, and the unburned component is checked. Therefore, the air ratio control and the unburned component check can be performed using one oxygen sensor. In the method of (3) and the apparatus of (6), the heater of the oxygen sensor is used in order to prevent unburned components from adhering to the oxygen sensor during use and causing erroneous detection and performance degradation. The unburned components adhering are burned, and the oxygen sensor is regenerated. This makes it possible to maintain the reliability of burner combustion control over a long period of time.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the principle of detecting the oxygen concentration under the applied voltage of the air ratio control voltage and the principle of detecting the unburned components under the unburned detection voltage near 0 V will be described below. First, the principle of detecting the oxygen concentration under the applied voltage of the air ratio control voltage will be described with reference to FIGS. In the fuel gas lean region, when a voltage is applied to the zirconia solid electrolyte 21 and a current is forced to flow under a temperature condition of a certain fixed value (for example, 650 ° C.) or more, as shown in the upper half lean region of FIG. , O ²⁻ from the cathode to the anode side through the solid electrolyte 21.
Ion transfer occurs (in FIG. 1, i indicates the current due to the transfer of O ²⁻ ions). This movement of O ²⁻ ions is detected as a current value (by the current detector 3 in FIG. 4), and increases linearly with an increase in the applied voltage. However, when the diffusion layer 24 is provided on the cathode side to control the diffusion of oxygen molecules,
Even when the applied voltage is increased, the output current value saturates at a constant value (see the left half of FIG. 3). In a region where the output voltage is saturated, when the applied voltage is constant (V ₀ , for example, 0.7 V), the oxygen concentration and the saturated output current value have a substantially linear relationship (see the right half of FIG. 3).

Therefore, when a constant applied voltage is applied, if the current value output from the oxygen sensor is controlled to a predetermined current value (when the current value is larger than the predetermined value, the air supply is throttled, and Is smaller than a predetermined value (by increasing the supply of air), the oxygen concentration in the exhaust gas can be controlled to the target value.
The air ratio control can be performed using the characteristics of the oxygen sensor. However, in the case of air ratio control, it is necessary to apply a constant applied voltage to the oxygen sensor and use a region where the output current is saturated.

Next, the principle of detecting unburned components will be described. In the fuel gas rich region, as shown in the lower half rich region of FIG. 1, there is no oxygen molecule in the exhaust gas, and HC, H ₂ , CO, etc., which are unburned components, are contained in the exhaust gas. .
When tested under the same conditions as in the fuel gas lean area,
O ₂ ions move from the anode to the cathode through the solid electrolyte 21 to generate an electromotive force V ₁ . This movement of O ₂ ions occurs in the opposite direction to the case of fuel gas lean,
_{When 1} > V, the direction of the current i is also reversed. In the characteristic of the applied voltage V-current i in FIG. 2, the characteristic shown in the negative region of FIG. 2 (i.e., when the air-fuel ratio A / F is 14 , 12).

In the case of burner combustion, it differs from the above-described fuel gas lean state and fuel gas rich state. Since the burner combustion is performed with the air ratio (the air ratio is 1 when complete combustion is performed) greater than 1, the exhaust gas of the burner combustion contains O ₂ , HC, H ₂ , CO, etc. , The lower half of FIG. 1 contains O ₂ . In this case, it was recognized by the inventor that when the test was performed under the same conditions as in the case of the fuel gas lean region, in FIG. 2, the Vi characteristics were slightly reduced (characteristics indicated by alternate long and short dash lines). This decrease δ is the effect of the unburned component.
δ increases as the amount of unburned components increases. However, in the characteristics indicated by the one-dot chain line, in the region where the applied voltage (0.7 V) is constant, the decrease δ in the Vi characteristics is equal to the air-fuel ratio A /.
It is caused by the decrease of F or HC in exhaust gas.
It is not possible to determine whether it is caused by the inclusion of H ₂ and CO. Therefore, the conventional Vi characteristic at a constant applied voltage cannot be used for detection and control of unburned components.

However, if the applied voltage is set to 0 (making the applied voltage 0) is equivalent to turning off the applied voltage or 0
When it is near, the Vi characteristic is determined by the HC and H in the exhaust gas.
_2. It has been discovered by the inventors that it can be used to detect the amount of unburned components such as CO. The reason is as follows. In FIG. 2, in the region where O ₂ is present in the exhaust gas (almost equal to the region where the current i is positive), the Vi characteristic line is always at point 0 (origin) even if the air-fuel ratio A / F changes.
And the Vi characteristic line becomes one line near 0V. This means that when the applied voltage V is 0 or around 0 V, the Vi characteristics are not affected by the air-fuel ratio, that is, are not affected by whether or not the exhaust gas contains O ₂ . Furthermore, it was also recognized that when the applied voltage was around 0 V, the Vi characteristics decreased due to the unburned components, and that the decrease δ still had a correlation with the amount of the unburned components. Therefore, if the applied voltage is set to around 0 or 0 V and the output current value is measured, the approximate value of the amount of unburned components in the exhaust gas can be detected without being affected by the air-fuel ratio, and thus the air ratio. . The present invention has been made based on this finding.

Next, a method and an apparatus for controlling the combustion of a burner according to an embodiment of the present invention will be described with reference to FIGS. The element itself of the oxygen sensor according to the embodiment of the present invention has the same structure as that of the on-vehicle lean mixture sensor, but the applied voltage applied thereto can be switched, and the same one oxygen sensor is used for air ratio control and unburned component detection. That it can be used, that there is a control box to control its switching,
In addition, regeneration from sensor deterioration is possible,
This is different from the air-fuel ratio control system using the in-vehicle lean mixture sensor in such points.

The burner combustion control device according to the embodiment of the present invention
As shown in FIG. 4, an oxygen sensor 20 having a solid electrolyte 21, an applied voltage switching means 2 for switching an applied voltage of the oxygen sensor 20 between an air ratio control voltage and an unburned detection voltage near 0 V, Unburned component concentration check means (FIG. 1 stored in the control box 18) for checking the unburned component concentration in the exhaust gas based on the magnitude of the negative output current of the oxygen sensor when the applied voltage is at the unburned detection voltage. 5 corresponding to step 102 of the control routine).
The burner combustion control device according to the embodiment of the present invention further includes an air ratio control unit (FIG. 5 stored in the control box 18) that executes the air ratio control when the applied voltage is at the air ratio control voltage.
(Means corresponding to step 103 of the control routine). Burner combustion control device. The burner combustion control device according to the embodiment of the present invention further determines whether or not an abnormality has occurred in the output of the oxygen sensor. If an abnormality has occurred, the oxygen sensor regeneration execution means (the control box 18) executes the oxygen sensor regeneration. Corresponding to the control routine of FIG.

As shown in FIG. 4, the oxygen sensor 20 includes a zirconia solid electrolyte 21 formed in a test tube shape, platinum electrodes 22 and 23 provided on the inner and outer surfaces of the solid electrolyte 21, and an outer surface of the outer electrode 23. A diffusion-controlling layer 24 made of a ceramic coating and a device (21, 22, 23,
The heater includes a heater (for example, a ceramic heater) 25 for maintaining the temperature at about 650 ° C. or higher, and a protective cover 26 provided outside the element. Sign 2
Reference numeral 7 denotes a heater lead wire.

The inner electrode 22 and the outer electrode 23 are connected to the applied voltage power supply 1 by lead wires 28 and 29, respectively. The applied voltage power supply 1 is supplied with an air ratio control voltage (for example,
0.6-0.7V) and an unburned detection voltage (0V) around 0V.
, That is, including a case where the circuit is switched to a circuit having no power supply). This switching is performed by a command signal from the control box 18 (or may be performed manually). A circuit connecting the inner electrode 22 and the outer electrode 23 to the applied voltage power supply 1 includes an oxygen sensor output current detection circuit for detecting the output current of the oxygen sensor 20 and outputting it to the control box 18 in series with the applied voltage power supply 1. A vessel 3 is provided.

The control box 18 stores a control routine shown in FIG. 5 and a control routine shown in FIG. When the burner combustion is started, the control routine of FIG. 5 is interrupted at predetermined time intervals. In step 101, it is determined whether the timer is on. This timer consists of a timer that repeats a cycle with ON being time T ₁ and OFF being time T ₂ . If it is determined in step 101 that the timer is on, the process proceeds to step 102 in which the applied voltage of the oxygen sensor 20 is set to around 0 V (including 0 V) to check for unburned components, and in step 101 it is determined that the timer is off. Then, the routine proceeds to step 103, where the applied voltage of the oxygen sensor 20 is turned on (for example, 0.7 V) to execute the air ratio control. The process proceeds from steps 102 and 103 to the end. According to this control routine, a cycle consisting of the air ratio control by the oxygen sensor and the unburned component check by the oxygen sensor is repeated.

When the burner combustion starts, the control routine of FIG. 6 is interrupted at predetermined time intervals. In step 201, the time counter determines whether or not the check time has arrived. If the check time has not arrived, the process proceeds to the end. If it is determined that the check time has arrived, the process proceeds to step 202. In step 202, it is determined whether there is any abnormality in the output current value of the oxygen sensor. For example, the oxygen concentration in the exhaust gas becomes 21% when the fuel gas is cut off and only the air flows, but the oxygen sensor checks whether the oxygen concentration correctly outputs the reference current corresponding to the oxygen concentration of 21%, and outputs. If the current deviates from the reference current by a predetermined width, it is determined that an abnormality has occurred. If there is no abnormality, the process directly proceeds to the end. If it is determined that there is an abnormality, the process proceeds to step 203. The abnormality occurs, for example, when an organic substance adheres to the surface of the oxygen sensor and is thermally decomposed to lower the output current value.

In step 203, the ceramic heater 25 built in the oxygen sensor is turned on while flowing clean air to the oxygen sensor 20 to heat the element and burn the organic substances attached to the element surface. When the organic matter is fired,
The oxygen sensor 20 is regenerated to the original state or a state close to the original state. Next, the routine proceeds to step 204, where the check count of the timer is cleared to 0, and the time for the next reproduction is counted again.

Next, a method of controlling the combustion of the burner by the oxygen sensor according to the embodiment of the present invention will be described. The burner combustion control method using the oxygen sensor according to the embodiment of the present invention performs burner combustion based on the output current of the oxygen sensor 20 in a state where the applied voltage of the oxygen sensor 20 having the solid electrolyte is set to a non-combustion detection voltage near 0 V. A step of checking the concentration of unburned components in the exhaust gas. The burner combustion control method using the oxygen sensor according to the embodiment of the present invention includes the steps of: switching an applied voltage of the oxygen sensor 20 having a solid electrolyte between an air ratio control voltage and an unburned detection voltage near 0 V; Performing the air ratio control while the voltage is switched to the air ratio control voltage, and checking the unburned component concentration while the applied voltage is switched to the unburned detection voltage. Furthermore, the burner combustion control method using the oxygen sensor according to the embodiment of the present invention is characterized in that when organic matter due to combustion reaction adheres to the oxygen sensor 20 and the output current value changes from the initial value, the heater 25 of the oxygen sensor 20 is kept clean. And baking the attached organic matter by applying a current.

FIG. 7 shows a regenerative single burner.
The figure shows a change in the output current of the oxygen sensor 20 when the cycle consisting of executing the air ratio control with the applied voltage set to 0.7 V and then performing the unburned component check with the applied voltage set to 0 V is repeated. When the applied voltage was cut off (or the applied voltage was set to around 0 V) and the complete combustion occurred, the output current value of the oxygen sensor 20 was -2.3 mA (milliamps). When CO and HC start to be mixed in the exhaust gas, the oxygen sensor 2
The output current value of 0 decreases. In that case, if the decrease exceeds the allowable value (the value indicated by the dotted line in FIG. 7) (below the dotted line), the control box 18 issues an alarm,
At least one of measures of increasing the air supply amount and reducing the fuel gas supply amount is taken.

FIGS. 8 to 11 show a plurality of examples in which the burner combustion control method and apparatus using the oxygen sensor of the present invention are applied to a furnace. 8 and 9 show a case where a single regenerative burner 13 is installed in a furnace 11 and the regenerator 3 of the burner 13 is installed.
FIG. 2 shows a state in which the oxygen sensor 20 is installed between the zero and the supply / exhaust switching mechanism 40. As shown in FIG. 8, the furnace 11 is provided with a heat storage combustion burner 13. The heat storage combustion burner 13 is connected to a fuel gas supply system 14, an air supply system 15, and an exhaust system 19. I have. Reference numeral 12 indicates a flame.
The air supply system 15 has a blower 16 and a control valve 17 provided in a passage connecting the blower 16 and the heat storage combustion burner 13, and the opening of the control valve 17 is controlled by a signal from a control box 18. .

The output of the oxygen sensor 20 provided in the regenerative combustion burner 13 is sent to the control box 18, and when the applied voltage is turned on, the control box 18 determines the required supply amount of fuel based on the output current value of the oxygen sensor. The signal is sent to the control motor of the control valve 17 and the opening of the control valve 17 is controlled so that the supplied air amount becomes the required supplied air amount.

As shown in FIG. 9, the single regenerative combustion burner 13 is composed of a casing 34 and a regenerator 30 (ceramic or the like) having a plurality of passages accommodated in a cylinder 31 disposed in the casing 34. ), The burner tile 62 provided on one side of the heat storage body 30, the supply / exhaust switching mechanism 40 provided on the other side of the heat storage body 30, and the supply / exhaust switching mechanism 40 and the heat storage body 30. Burner tile 62
And a fuel injection nozzle 60 extending to 61 is a pilot air supply pipe.

The heat storage body 30 recovers the heat when passing the exhaust gas and stores the heat, and releases the heat stored when passing the main air for combustion to preheat the main air. Heat storage element 30
Is divided into a plurality of sections in the circumferential direction of the burner. When exhaust gas flows through some of the sections, air supply flows into other sections.
The supply and exhaust air passing through the heat storage body 30 is alternately switched by the switching mechanism 40. The burner tile 62 is made of ceramics or heat-resistant metal, and has a protruding portion 64 protruding from the air supply / exhaust surface 63. A fuel release surface 65 is formed from the inner surface to the tip of the protrusion 64, and a supply / exhaust hole 66 is opened in a supply / exhaust surface 63 outside the protrusion 64. The section of the supply / exhaust hole 66 and the heat storage body 30 corresponds to the circumferential direction of the burner. When exhaust gas flows through a part of the plurality of supply / exhaust holes 66, main air flows through the remaining supply / exhaust holes 66.

The supply / exhaust switching mechanism 40 includes a movable member 44.
And a fixing member 46 and a partition wall 41. Fixing member 4
6 has a plurality of through holes 47 corresponding to a plurality of sections of the heat storage body 30. The movable member 44 has an opening 42 provided on one side of the partition wall 41 and an opening 43 provided on the other side of the partition wall 41. The opening 42 communicates with the air supply hole 51, The opening 43 communicates with the exhaust hole 52. The movable member 44 is a driving means (motor, cylinder, etc.)
The through hole 47 which has been rotated in one direction or reciprocally by 45 to the opening
And the heat storage body 30 and the supply / exhaust hole 6
6. Switch the air supply and exhaust flow.

The oxygen sensor 20 is installed at a position between the switching mechanism 40 and the heat storage unit 30. The oxygen sensor 20 has a detection portion of the oxygen sensor 20 inserted into a through hole formed in the fixing member 46. Since this portion is located downstream of the heat storage body 30 in the exhaust gas flow direction, the temperature of the exhaust gas is reduced to approximately 300 ° C., which is desirable in terms of durability of the oxygen sensor 20. Also, in the supply air flow direction, the fixing member 4
6 is a part downstream of the sliding surface between the movable member 6 and the movable member 44, and is a part that is not affected by a leak from the supply air to the exhaust air on the sliding surface between the fixed member 46 and the movable member 44. Yes, it is the site where the true oxygen concentration of the exhaust can be measured. An oxygen sensor 20 is installed at this position to reduce the applied voltage to 0.
By monitoring the output current value near V, highly reliable detection and control of unburned components can be performed.

FIG. 10 shows a system in which a pair of alternately switching regenerative burners 13 are installed in a furnace 11. In this type of system, air supply and exhaust are switched by the burner 13.
This is performed by a switching valve (for example, a four-way switching valve) 70 provided in the middle of the air supply path 15 and the exhaust path 19 which are connected to each other, so that the switching mechanism 40 provided in the single burner is provided in the burner. I can't. Also, this type of burner system has a heat storage body 30,
0 need not be partitioned into multiple sections in the burner circumferential direction. Other configurations such as burner tiles and fuel supply pipes are the same as those of the single burner.

In the case of the alternately switching regenerative burner system,
The oxygen sensor 20 is provided in a portion between the heat storage body 30 and the switching valve 70 which is a switching mechanism of the supply and exhaust in the supply and exhaust passages 15 and 19. As a result, similar to the case of the single burner, the effect of improving the durability at low temperatures and not being affected by the leak can be obtained. Also, by installing the oxygen sensor 20 at this position and monitoring the output current value with the applied voltage near 0 V, highly reliable detection of unburned components can be achieved.
Control can be performed.

FIG. 11 shows a system in which a normal burner 13 of the non-thermal storage type is installed in the furnace 11. Burner 1
A fuel supply system 14 and an air supply system 15 are connected to 3. Reference numeral 12 indicates a flame. Air supply system 15
Has a blower 16 and a control valve 17 provided in a passage connecting the blower 16 and the burner 13, and the opening of the control valve 17 is controlled by a signal from a control box 18. Oxygen sensor 2 in furnace or flue 19
0 is provided. The output of the oxygen sensor 20 is sent to the control box 18 where the oxygen sensor 2
Calculate the required air supply amount for the fuel based on the output of 0,
The signal is sent to the control motor of the control valve 17, and the opening of the control valve 17 is controlled so that the supplied air amount becomes the required supplied air amount. By monitoring the output current value with the applied voltage of the oxygen sensor 20 at around 0 V, highly reliable detection and control of unburned components can be performed.

[0029]

According to the method of the first aspect and the apparatus of the fourth aspect, the voltage applied to the oxygen sensor is set to around 0 V (including the case where the voltage is 0 V), and the burner is output based on the output current value of the oxygen sensor at that time. Since the concentration of unburned components in the exhaust of combustion is checked, the concentration of unburned components in the exhaust can be checked without being affected by the value of the air ratio. High combustion can be performed. According to the method of the second aspect and the apparatus of the fifth aspect, in addition to the effects of the first and fourth aspects, the applied voltage can be switched, so that one oxygen sensor can be used for air ratio control and unburned component check. You can do both. According to the method of the third aspect and the apparatus of the sixth aspect, when the organic substance due to the combustion reaction adheres to the oxygen sensor and the output current value changes from the initial value, the heater of the oxygen sensor is energized in a clean state and adheres. Since the organic matter is burned, the performance of the oxygen sensor can be restored to the initial state, and highly reliable combustion with less emission of unburned components can always be performed.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing the flow of oxygen ions in an oxygen sensor used in a method and an apparatus according to an embodiment of the present invention in each of a fuel lean state and a rich state.

FIG. 2 is a characteristic diagram of an applied voltage (V) -output current (i) of an oxygen sensor used in the method and the apparatus according to the embodiment of the present invention.

FIG. 3 is a graph derived from FIG. 2 and showing the relationship between the output current (I) and the oxygen concentration when the applied voltage is constant.

FIG. 4 is a cross-sectional view of an oxygen sensor used in the method and apparatus according to the embodiment of the present invention, and a circuit diagram of the applied voltage.

FIG. 5 is a flowchart showing a control routine of air ratio control and unburned component check of the method and apparatus of the embodiment of the present invention.

FIG. 6 is a flowchart showing a control routine of sensor regeneration of the method and apparatus of the embodiment of the present invention.

FIG. 7 is a graph showing a relationship between an oxygen sensor output current and time when combustion is controlled by the method and the device according to the embodiment of the present invention.

FIG. 8 is a system diagram of a single-type heat storage combustion burner system according to the method and apparatus of the embodiment of the present invention.

FIG. 9 is a cross-sectional view of the single type heat storage combustion burner of FIG.

FIG. 10 is a system diagram of an alternately switching type twin thermal storage combustion burner system according to the method and apparatus of the embodiment of the present invention.

FIG. 11 is a system diagram of a normal burner combustion system according to the method and apparatus of the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Applied voltage power supply 2 Applied voltage switch 3 Output current detector 11 Furnace 18 Control box 20 Oxygen sensor 21 Solid electrolyte 22, 23 Electrode 24 Diffusion layer 25 Heater

Claims (6)

[Claims] A step of checking the concentration of unburned components in the exhaust gas of the burner combustion based on the output current of the oxygen sensor while the applied voltage of the oxygen sensor having a solid electrolyte is set to the unburned detection voltage near 0 V. Control method for burner using oxygen sensor. 2. A step of switching an applied voltage of an oxygen sensor having a solid electrolyte between an air ratio control voltage and an unburned detection voltage near 0 V, and the applied voltage is switched to an air ratio control voltage. Performing an air ratio control during the period, and checking the unburned component concentration while the applied voltage is switched to the unburned detection voltage. 3. The organic sensor according to claim 1, wherein when an organic substance due to a combustion reaction adheres to the oxygen sensor and the output current value changes from an initial value, a heater is supplied to the oxygen sensor in a clean state to burn the adhered organic substance. A burner combustion control method using the oxygen sensor described in the above. 4. An oxygen sensor having a solid electrolyte, an applied voltage switching means for switching an applied voltage of the oxygen sensor between an air ratio control voltage and an unburned detection voltage near 0 V, A burner combustion control device using an oxygen sensor, comprising: an unburned component concentration check unit for checking the unburned component concentration in exhaust gas based on the magnitude of the negative output current of the oxygen sensor when the voltage is at the operating voltage. 5. An oxygen sensor having a solid electrolyte, an applied voltage switching means for switching an applied voltage of the oxygen sensor between an air ratio control voltage and an unburned detection voltage near 0 V, Unburned component concentration checking means for checking the unburned component concentration in the exhaust gas based on the magnitude of the negative output current of the oxygen sensor when the voltage is at the operating voltage, and the air ratio control when the applied voltage is at the air ratio controlling voltage And an air ratio control unit for executing the combustion control. 6. The burner according to claim 4, further comprising an oxygen sensor regeneration executing means for judging whether or not an abnormality has occurred in the oxygen sensor output, and executing the oxygen sensor regeneration if an abnormality has occurred. Combustion control device.