JPH1038262A - Regenerative combustion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To operate at an excess air ratio which is optimum or stabilized close to the optimum value by providing an O2 sensor in a regenerative burner and/or an air supply and exhaust passage in a regenerative combustion device which uses the O2 sensor for the control of the excess air ratio. SOLUTION: A regenerative burner 13 is connected to a gaseous fuel supply system, 14 an air supply line 15 and an exhaust line 19, for example. An O2 sensor 20 is provided in the burner 13 or in the air supply and exhaust lines 15 and 19 of this burner 13. The control method of this device is designed to detect O2 concentration by a current value signal transmitted from the O2 sensor 20 and control an excess air supply ratio based on the O2 concentration wherein the aforesaid air ratio refers to an air excess air ratio which a theoretical amount of air required in the case of perfect combustion). As for the O2 sensor 20 employed, a lean mixture sensor or its improved type sensor, for example, which is employed for cars, is used herein. Preferably, a pair of alternatingly switchable burner systems be adopted for this burner 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat storage combustion device, and more particularly to a heat storage combustion device using an O ₂ sensor for controlling an air ratio.

[0002]

2. Description of the Related Art Conventionally, a heat storage combustion system is known from Japanese Patent Application Laid-Open No. Hei 4-270819. Where,
The high-temperature exhaust gas is discharged through the regenerator, the heat of the exhaust gas is stored in the regenerator, and then when the supply and exhaust are switched and the air supply passes through the regenerator, the heat stored is released to the air supply to supply the air. And thereby significantly improve thermal efficiency.

[0003]

However, in the conventional thermal storage combustion system, the heat storage element, that is, the leakage of the supply air to the exhaust in the supply / exhaust switching mechanism and the pressure fluctuation due to the temperature (causing a change in the volume flow rate). (Change in pressure loss), the air ratio changes, and there is a problem that it is difficult to continue combustion at an optimum air ratio for a long time. SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat storage combustion device that can be operated at a stable air ratio, which is optimal or close thereto.

[0004]

[MEANS FOR SOLVING THE PROBLEMS]
The device of Ming is as follows. (1) A heat storage combustion burner, and the heat storage combustion burner
Is the O installed in the supply and exhaust path_TwoSensor and body
Heat storage combustion device. (2) The regenerative combustion burner is a switch between a regenerator and a supply / exhaust gas
The O_TwoA sensor comprising the heat storage element and the switching mechanism
(1) The heat storage combustion device according to (1), which is installed between the heat storage device and the storage device. (3) The O_TwoSensor is O for car_TwoIs a sensor
The heat storage combustion device according to (1) or (2). (4) Further, self-diagnosis means is provided (1)
Is a heat storage combustion device according to (2) or (3). (5) The O_TwoThe heat storage and combustion chamber in which the sensor is installed
The heat storage and combustion bar
From the supply / exhaust flow path in the supply / exhaust path.
A recess is formed therein, and the O_TwoC
The heat storage combustion device according to (1), wherein the sensor is installed. (6) Heat storage wherein the heat storage combustion burner has a rectifying function
Having the body, _TwoNear the sensor installation site
A member that disturbs the flow of exhaust gas from the heat storage body is provided.
(5) The heat storage combustion device according to (5).

[0005] In the regenerative combustion device of the above (1), utilizing the fact that exhaust gas returns to the burner after circulating in the furnace, an O ₂ sensor is provided in the burner or its supply / exhaust path, and the O ₂ sensor is installed at the O ₂ sensor installation site. of O ₂ to detect the concentration, perform air ratio control based on the output current value. As a result, it is possible to control with a stable air ratio which is optimal or close thereto. In the heat storage combustion device of the above (2), since the O ₂ sensor is installed in a portion after the exhaust gas has passed through the heat storage body, the temperature is relatively low, and the durability of the sensor is improved. Further, since the O ₂ sensor is provided downstream of the supply / exhaust switching mechanism in the supply air flow direction, it is not affected by leakage from the supply air to the exhaust gas. For this reason, the air ratio control becomes highly reliable. In the heat storage combustion device of the above (3), the use of the on-vehicle O ₂ sensor as the sensor makes the cost and size small, and also improves the responsiveness and the response reliability. Since the heat storage combustion device of the above (4) has a self-diagnosis means, it is possible to perform self-diagnosis of deterioration of the sensor, heat storage element leak, switching mechanism blower failure, and the like. In the regenerative combustion device of the above (5), since the O ₂ sensor is provided in the depression, it is possible to prevent a large amount of air from hitting the O ₂ sensor when the air is flowing to the O ₂ sensor portion, and the element temperature to drop transiently. Can be prevented. Further, when the exhaust gas is flowing to the O ₂ sensor portion, it is possible to prevent the O ₂ sensor from fiercely spreading the oxygen concentration unevenness of the exhaust gas, causing the output current value to fluctuate excessively and lose stability. In the heat storage combustion device of the above (6), if an O ₂ sensor is provided in the depression, the turbulent air supply easily flows into the depression, but the exhaust rectified by the heat storage body does not easily flow into the depression. O ₂ output current value of the sensor becomes higher than the actual furnace oxygen concentration, since the member for disturbing the flow of exhaust gas from the regenerator to the installation site near the O ₂ sensor is provided, also easily dent exhaust The O ₂ sensor can output an output current value equal to the actual oxygen concentration in the furnace.

[0006]

Embodiments of the present invention will be described below. FIG. 1 shows an example of the apparatus according to the embodiment of the present invention.
In FIG. 1, a furnace 11 is provided with a burner 13 for regenerative combustion, and the burner 13 for regenerative combustion includes a fuel (for example, gaseous fuel) supply system 14, an air supply path 15, and an exhaust path 19. And are connected. Reference numeral 12 indicates a flame formed by the heat storage combustion burner 13. Supply path 1
5 is connected to a blower 16 for sending combustion air to the regenerative combustion burner 13, and a control valve 1 is connected to a path connecting the blower 16 and the regenerative combustion burner 13.
The opening of the control valve 17 is controlled by a signal from the control box 18. Feeding the regenerative combustion burner 13 or regenerative combustion burner 13, the exhaust path 15, 19, O ₂ sensor for detecting the O ₂ concentration (oxygen sensor, also referred to as detector) 20 is provided. The output (output current value) of the O ₂ sensor 20 is sent to the control box 18, where the control box 18 calculates the required supply amount of fuel based on the output of the O ₂ sensor 20, and sends the signal to the control valve 18. The control valve 17 is sent to the control motor 17a to control the opening of the control valve 17 so that the supplied air amount becomes the required supplied air amount.

The heat storage combustion burner 13 may be a single burner provided with a supply / exhaust alternate switching mechanism 40 shown in FIG. 8, or a twin burner shown in FIG. May be of a type that is alternately switched according to. When the heat storage combustion burner 13 is a single burner, as shown in FIG. 8, the heat storage combustion burner 13 is housed in each of a casing 34 and a plurality of cylinders 31 arranged in the casing 34.
A heat storage body 30 (having a honeycomb type ceramic body, a bundle of metal rods or heat-resistant material rods, etc.) having a number of passages, and a burner tile 6 provided on one side of the heat storage body 30
2, a supply / exhaust switching mechanism 40 provided on the other side of the heat storage 30, and a fuel injection nozzle 60 extending to the burner tile 62 through the supply / exhaust switching mechanism 40 and the heat storage 30.
And consisting of 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, and when exhaust gas flows through some of the sections, main air serving as 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. Burner tile 62
Is made of ceramics or heat-resistant metal,
3, a plurality of supply / exhaust holes 66 opened in the supply / exhaust surface 63,
It 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 portion of the supply / exhaust surface 63 outside the protrusion 64. Supply / exhaust hole 66 and heat storage body 3
The section 0 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 fixed member 46, and the movable member 44 has a partition wall 41 that partitions air supply and exhaust. The fixing member 46 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. One opening 42 is provided with an air supply port 51.
The other opening 43 is in communication with the exhaust port 52. The movable member 44 is rotated in one direction or reciprocatingly by a driving means (a motor, a cylinder, or the like) 45, and the through hole 47 which has been aligned with the opening 42 so far.
Is made to coincide with the opening 43, and the through-hole 47 that has been coincident with the opening 43 is made coincident with the opening 42, thereby switching the flow of air supply and exhaust of the heat storage body 30 and the supply / exhaust hole 66. .

The O ₂ sensor 20 includes a heat storage combustion burner 13.
Is composed of a single burner, it is installed at a portion between the switching mechanism 40 (more specifically, the sliding surface of the fixed member 46 and the movable member 44 of the switching mechanism 40) and the heat storage body 30. In the example of FIG. 8, the O ₂ sensor 2 is provided in a recess 48 formed by a through hole formed in the fixing member 46 by increasing the thickness of the fixing member 46.
The O ₂ sensor 20 is installed with the zero detection unit inserted. Since the installation site of the O ₂ sensor 20 is located downstream of the heat storage unit 30 in the exhaust gas flow direction, the temperature of the exhaust gas is
At 0, the temperature is reduced to about 300 ° C. Since the O ₂ sensor 20 is not exposed to a high temperature, the durability of the O ₂ sensor 20 is improved. In addition, in the supply air flow direction, the portion is located downstream of the sliding surface between the fixed member 46 and the movable member 44 of the switching mechanism 40, and the sliding surface between the fixed member 46 and the movable member 44 allows the air to flow from the air supply to the exhaust. Even if a leak occurs, it is a part that is not affected by the leak, and is a part where the O ₂ concentration of the true exhaust gas can be measured. Therefore, when the O ₂ concentration can be detected with high accuracy and the air ratio control is performed based on the O ₂ concentration, highly accurate and highly reliable control can be performed.

As shown in FIG. 9, the heat storage combustion burner 13 may be composed of a pair of combustion alternately switching type burners. In this type of system, switching between air supply and exhaust
A switching valve (for example, a four-way switching valve) 70 provided in the air supply path 15 and the exhaust path 19 connected to the burner 13.
Therefore, the switching mechanism 40 provided in the case of the single burner is not provided in the burner 13. Although this type of burner 13 has the heat storage body 30, the heat storage body 30 does not need to be divided into a plurality of sections in the circumferential direction of the burner. Other configurations such as burner tiles and fuel supply pipes are the same as those of the single burner.

[0012] For a system having a pair of burners 13 shown in FIG. 9, O ₂ sensor 20 is fed, the exhaust path 15, 1
9 is provided in a portion between the heat storage body 30 and a switching valve 70 which is a switching mechanism of supply and exhaust. As a result, the same operation and effect as those of the single burner can be obtained (the operation and effect that the portion where the O ₂ sensor 20 is installed is relatively low in temperature and the durability is improved, and the leakage between the supply and exhaust is not affected).

Preferably, as shown in FIGS. 10 to 13, a heat storage combustion burner 13 provided with an O ₂ sensor 20 is provided.
Alternatively, a heat storage combustion burner or a depression 48 withdrawn from a supply / exhaust flow path in the supply / exhaust path is formed in the supply / exhaust paths 15 and 19, and an O ₂ sensor is provided in the depression 48. 20 detection units (elements) 20a are provided. The present invention includes a case where the detection unit 20a is installed so as to protrude into a supply and exhaust flow path, but it is more preferable that the detection unit 20a be retracted into the depression 48. Also, preferably,
As shown in FIGS. 10 and 11, when the heat storage combustion burner 13 has a heat storage body 30 having a rectifying function, a member that disturbs the flow of exhaust gas from the heat storage body 30 near the installation site of the O ₂ sensor 20. (For example, a baffle plate) 49 is provided. The case where the member 49 is not provided is also included in the present invention, but it is more preferable that the member 49 is provided.

The reason is as follows. O ₂ detection unit of the sensor 20 (element) 20a is fed and provided so as to protrude into the flow channel of the eduction, O ₂ sensor 20 is reproducible shake minutely the output current value faithfully pick for the oxygen concentration unevenness of the exhaust, Stability decreases. Further, at the time of air supply, a large amount of air directly hits the O ₂ sensor 20 and the element temperature decreases, so that it is necessary to increase the heater voltage.
When O ₂ detection unit of the sensor 20 (element) 20a of the recess retracted within 48 installed, it is possible to prevent a significant reduction in device temperature during the hypersensitive response and air supply of the O ₂ sensor 20.

When the detecting portion (element) 20a of the O ₂ sensor 20 is retracted into the recess 48, the air at the time of air supply is indented.
To the detection unit (element) 20a without any problem. However, since the exhaust gas immediately after leaving the heat storage unit 30 has directivity (laminar flow), only a small amount enters into the depression 48, and when the air is supplied, the exhaust 48
The stagnant air that has entered cannot be completely scavenged. As a result, the output current value of the O ₂ sensor 20 becomes higher than the actual oxygen concentration in the furnace, and the combustion air (supply air) is reduced by the air-fuel ratio control.
However, a member (for example, a baffle plate) that disturbs the flow of exhaust gas 4
By providing 9, the exhaust gas hits the member 49 and is disturbed, flows around the back side of the member 49, flows into the depression 48, and hits the detection unit 20 a of the O ₂ sensor 20. Then, at the time of air supply, the air accumulated in the depression 48 is quickly scavenged, and the exhaust gas continues to enter around the O ₂ sensor 20. As a result, the output current of the O ₂ sensor 20 shows a substantially constant value, which matches the value corresponding to the actual oxygen concentration in the furnace. Further, in order to obtain a smooth scavenging of the air supply immediately after switching of the air supply and exhaust, the shape of the bottom of the depression 48 may be an R shape or a taper shape as shown in FIGS. Good.

O_TwoFor example, the sensor 20
More O_TwoO for detecting the concentration _TwoFrom the sensor
In this case, the structure shown in FIG. 2 is adopted. O_TwoSensor 20
Is a zirconia solid electrolyte 21 formed into a test tube mold,
Platinum electrodes provided on inner and outer surfaces of zirconia solid electrolyte 21
22, 23, and a ceramic applied to the outer surface of the outer electrode 23
Diffusion-controlling layer 24 composed of
(A part consisting of 1, 22, 23, 24)
Heater maintained at 0 ° C or higher (for example, ceramic heater)
25 and a protective cover 26 provided outside the element.
Have. Reference numeral 27 denotes a heater lead wire, and reference numeral 28 denotes an inside power supply.
The pole lead, reference numeral 29 indicates the outer electrode lead.
You.

FIGS. 3 to 6 show the principle of detecting the O ₂ concentration of the O ₂ sensor 20 which detects the O ₂ concentration based on the output current value.
This will be described with reference to FIG. A certain value (for example, 650 °
C) When a voltage is applied to the zirconia solid electrolyte 21 under the above temperature conditions and a current is forced to flow, O ²⁻ ions move through the solid electrolyte 21 as shown in FIG. This O ²⁻ ion transfer amount is detected as a current value and linearly increases with an increase in applied voltage. However, when the diffusion controlling layer 24 is provided on the cathode side to control the diffusion of oxygen molecules, the output current value is saturated at a constant value even when the applied voltage is increased (see FIG. 6). Then, in a region where the output current value is saturated, when the applied voltage is constant (V ₀ ),
The O ₂ concentration and the saturation output current value have a substantially linear relationship (see FIG. 6).

The output characteristic of the O ₂ sensor 20 as shown in FIG. 2 is as shown in FIG. 3, similarly to the relationship between the element of FIG. 5 and FIG. When the applied voltage is changed, stable saturation current characteristics can be obtained over a wide range of air-fuel ratios. FIG.
Is an output current characteristic at an element temperature of 700 ° C. and an applied voltage of 0.7 V. An almost linear characteristic is obtained in an air-rich combustion atmosphere.

Generally, in the case of furnace combustion in a burner, combustion is not performed in a gas-rich atmosphere, but is performed in an air-rich atmosphere. In this case, O ₂ is burned with a surplus of at least about 0.5% to at most about 21%. Therefore, it is within the operating range of the O ₂ sensor 20. In this case, the unburned matter generation limit O is controlled by performing feedback control to the control motor 17a of the control valve 17 based on the O ₂ concentration in the furnace detected by the O ₂ sensor 20.
Low O ₂ combustion at around ₂ concentrations is possible.

The combustion control method implemented by using the above-described apparatus includes a heat storage combustion burner 13 or its supply and exhaust path 1.
And detecting the O ₂ concentration by the current value signal from the O ₂ sensor 20 provided in the 5 and 19, based on the detected O ₂ concentration was supply to the theoretical amount of air required in the case of air ratio (complete combustion Controlling the ratio of air). In this combustion control, for example, a lean mixture sensor used in an automobile or an improved version thereof can be used as the O ₂ sensor 20 used. Since there is no problem in terms of space at the time of installation, and the current output type, the responsiveness is high and the response reliability of the control is improved.

For example, HI-
When LO-OFF combustion is performed (HI and L at the set temperature)
An example of a control method for switching O and switching between LO and OFF at the set temperature + α (α is a small positive value) will be described below. Here, HI indicates high combustion, LO indicates low combustion, and OFF indicates main fuel cut. (1) Cooling furnace startup: HI or LO combustion. The control motor 17a (control valve 17
) Is fully open. The O ₂ sensor 20 is not activated until a certain temperature or time. Thereafter, the O ₂ sensor 20 controls the air (supply) flow rate (meaning that the output signal of the O ₂ sensor 20 is sent to the control box and the operation signal of the control box is sent to the control motor 17a, the same applies hereinafter). . (2) Switching from HI to LO: Switching to LO combustion while keeping the control motor constant (to avoid generating CO due to incomplete combustion). Then, the O ₂ sensor 20 controls the air (supply) flow rate. (3) Switching from LO to OFF: shut off the main fuel. Purge and purge with appropriate amount of air using the control motor. (4) Switching from OFF to LO: After the control motor is fully opened, LO combustion is ignited and LO combustion is performed (to prevent CO from being generated due to incomplete combustion). Then, O ₂ sensor 2
0 controls the air (air supply) flow rate. (5) Switching from LO to HI: After fully opening the control motor (and the control valve), HI combustion is ignited and HI combustion is performed (to prevent CO from being generated due to incomplete combustion). Then, the O ₂ sensor 20 controls the air (supply) flow rate. By the above combustion, low O ₂ combustion and suppression of emission of CO into the atmosphere can be achieved.

FIG. 7 shows the air ratio control in the combustion control.
In the process, self-diagnosis (O _TwoDeterioration of sensor 20
And self-diagnosis of combustion equipment failure)
1 shows a combustion control device according to the first embodiment. Control of FIG.
The routine is controlled by control box 18 (eg, a computer).
Data).

The routine shown in FIG.
(ΔT is about 30 seconds or less). Stay
In Step 101, O_TwoSite where the sensor 20 is installed
Indicates whether air is flowing (or exhaust is flowing)
judge. If yes, O _TwoThe sensor installation site is air
Rich (O_TwoConcentration is large). If NO, O_TwoSen
The installation site is O_TwoThe concentration is low.

When it is determined NO in step 101
Proceeds to step 102 where O _TwoSensor 20
The output signal value is larger than a predetermined value B (for example, 3 mA)
(O_TwoLarge amount) or not (O_TwoIs small). Place of greatness
If the amount of oxygen in the exhaust
Because it tastes, go to step 103 and
The control valve is turned to the closed side, and then E
Proceed to ND step. In addition, if the air supply is low,
Go to step 104.
Command the increase in air supply and turn the control valve to the open side.
Invert. Then, from step 104 to step 105
And go to O_TwoOutput current value of sensor 20 is lower limit
It is determined whether the value is equal to or less than a value C (a value smaller than B). Under settings
If it is larger than the limit value C, the process directly proceeds to the END step.
However, at step 105_TwoOutput current value of sensor 20
Is smaller than the set lower limit C, the air supply is increased in step 104.
Even if the amount is indicated, the air supply will not increase beyond the set lower limit.
Therefore, some failure in the air supply system (even if
In this case, the heat storage body 30 has a leak from the supply air to the exhaust.
Large, blower failure, etc.)
And the process goes to step 106 to shut down the system (furnace combustion).
Stop. That is, pass the route of step 106
Is to self-detect that a system error has occurred.
This means that you have diagnosed yourself.

If YES in step 101 (O
If the air supply is flowing to the ₂ sensor installation site), the process proceeds to step 107, where it is determined whether or not the output signal of the O ₂ sensor 20 is larger than a predetermined value A (a value larger than B, for example, 35 mA). judge. Since the O ₂ sensor 20 installation portion is when the air supply is flowing O ₂ sensor installation site in a state of Earitchi, since the O ₂ sensor 20 is naturally outputs the value of the predetermined value A abnormal if successful , Step 107
If it is determined that is larger than A in step 108, the process proceeds to step 108 to continue the operation, and proceeds to the END step.

[0026] However, if it is determined following the A in step 107, the O ₂ sensor 20 installed site regardless of a state of Earitchi, the output signal of the O ₂ sensor 20 is O
_Since it is not possible to output a large output corresponding to the _two quantities, it means that the O ₂ sensor 20 itself has failed due to sensor deterioration, etc. (If the O ₂ sensor deteriorates, the output current value gradually decreases. Become). Therefore, in that case, the process proceeds to step 109, where a sensor deterioration alarm (alarm or the like) is issued, and the system is shut down (furnace combustion is stopped) as necessary. However, since it is not necessary to shut down the system immediately after the O ₂ sensor has deteriorated, the system may be shut down after an appropriate time has passed after a sensor deterioration alarm (alarm etc.) is issued, or the furnace operation may be stopped. In some cases, only the O ₂ sensor 20 may be replaced while continuing. In any case, to pass through the route of step 109 means that an abnormality occurs in the O ₂ sensor 20, the deterioration of the O ₂ sensor 20 (or abnormal) are self-diagnosis.

By having such a self-diagnosis function, the reliability of the heat storage combustion device of the embodiment of the present invention and its combustion control is enhanced. Further, even if an abnormality occurs, it is possible to determine whether the abnormality is on the system side or on the sensor side, and appropriate measures can be taken. Furthermore, there is an advantage that these self-diagnosis are always performed during operation of the furnace.

[0028]

According to the first aspect of the present invention, an O ₂ sensor is provided in the burner or its supply / exhaust passage to detect the O ₂ concentration, and the air ratio control is performed based on the output current value.
This stabilizes the air ratio. In the thermal storage combustion device according to the _{second aspect} , the O2 sensor is provided at a position after the exhaust gas has passed through the thermal storage body, so that the temperature is relatively low, and the durability of the sensor is improved. Further, since the O ₂ sensor is provided downstream of the supply / exhaust switching mechanism in the supply air flow direction, it is not affected by leakage from the supply air to the exhaust gas. For this reason, the control becomes highly reliable. In the thermal storage combustion device according to the third aspect, by using an on-vehicle O ₂ sensor as the sensor, the cost is reduced, the size is reduced, the response is improved, and the response reliability is improved. Since the heat storage combustion device according to the fourth aspect has the self-diagnosis means, it is possible to perform self-diagnosis of deterioration of the sensor, heat storage element leak, switching mechanism blower failure, and the like. In the thermal storage combustion device according to the fifth aspect, since the O ₂ sensor is provided in the depression, it is possible to prevent a large amount of air from hitting the O ₂ sensor when the air is flowing to the O ₂ sensor portion, thereby preventing the element temperature from dropping excessively. it can also be prevented O ₂ sensor is eliminated can faithfully picked output current value is stable vibration sensitively oxygen density unevenness in the exhaust when the exhaust to O ₂ sensor site is flowing. In the thermal storage combustion device according to the sixth aspect, since a member that disturbs the flow of exhaust gas from the thermal storage element is provided near the installation site of the O ₂ sensor, the exhaust gas can also easily flow into the hollow, The O ₂ sensor can output an output current value equal to the actual oxygen concentration in the furnace.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a heat storage combustion device according to an embodiment of the present invention.

FIG. 2 shows O ₂ used in the combustion control method according to the embodiment of the present invention.
It is sectional drawing of a sensor.

FIG. 3 is a graph showing a relationship between an output current (mA) and an applied voltage (V) by the O ₂ sensor of FIG. 2;

4 is a graph showing a relationship between an output current (mA) by an O ₂ sensor of FIG. 2 and an air-fuel ratio (air / fuel).

FIG. 5 is a sectional view of the vicinity of a solid electrolyte showing the principle of detecting the oxygen concentration of the O ₂ sensor used in the embodiment of the present invention.

FIG. 6 is a graph showing a relationship between an output current / applied voltage and an output current / O ₂ concentration of a detector portion in FIG. 5;

FIG. 7 is a flowchart of a control routine of a device having a self-diagnosis function according to the embodiment of the present invention.

FIG. 8 is a sectional view of a single burner used in the heat storage combustion device of the embodiment of the present invention.

FIG. 9 is a cross-sectional view of a system having a twin burner used in the heat storage combustion device according to the embodiment of the present invention.

FIG. 10 is a cross-sectional view of the vicinity of a portion where an O ₂ sensor is installed in the heat storage combustion device according to the embodiment of the present invention.

FIG. 11 is a plan view of the device part of FIG. 11;

FIG. 12 is a cross-sectional view when the bottom surface of the recess is formed in an R shape in the device portion of FIG. 11;

FIG. 13 is a cross-sectional view when the bottom surface of the dent is tapered in the device portion of FIG. 11;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 Furnace 12 Flame 13 Burner for heat storage combustion 14 Fuel system 15 Air supply system 16 Blower 17 Control valve 18 Control box 19 Exhaust system 20 O ₂ sensor 48 Depression 49 Member that disrupts flow (for example, baffle plate)

Claims (6)

[Claims] 1. A heat storage combustion device comprising: a heat storage combustion burner; and an O ₂ sensor installed in the heat storage combustion burner or its supply / exhaust path. 2. The regenerative combustion device according to claim 1, wherein the regenerative combustion burner has a switching mechanism for switching between a regenerator and a supply / exhaust gas, and the O ₂ sensor is installed between the regenerator and the switching mechanism. . 3. The heat storage combustion device according to claim 1, wherein the O ₂ sensor is a vehicle-mounted O ₂ sensor. 4. The heat storage combustion device according to claim 1, further comprising self-diagnosis means. 5. The heat storage combustion burner in which the O ₂ sensor is installed, or a supply / exhaust path for the heat storage combustion burner or a depression recessed from a supply / exhaust flow path in the supply / exhaust path in the heat storage combustion burner. There are formed, regenerative combustion apparatus according to claim 1, wherein the O ₂ sensor in the depressions only is installed. 6. The heat storage combustion burner has a heat storage element having a rectifying function, and a member that disturbs the flow of exhaust gas from the heat storage element is provided near a location where the O ₂ sensor is installed. 6. The heat storage combustion device according to 5.