JPH10103667A - Combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a combustor capable of accurately grasping abnormal combustion conditions in the combustor for detecting normal/abnormal conditions of a burner. SOLUTION: A controller 28 when in a tentative judgment performed in combustion abnormal combustion is shown by any of a detected value from a flame rod current detector 25 and a detected value from a fan driving current detector circuit 31, detects a fan driving current value in the state where a fan is rotated at a high speed upon post purging, and judges whether or not the combustion is normal based upon the detected fan driving current detected value. The controller 28 when any one of the FR current detection value and the fan driving current detected value indicates abnormal combustion, performs main judgment excepting the case where a mode to limit the main judgment is set. When the mode to limit the main judgment is set, the operation is prevented from being transferred until the mode is released. Provided the abnormal combustion is judgment in the main judgment, the controller completes a series of abnormality judgment operations after the abnormal combustion is dealt with.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a combustion apparatus which detects a combustion state of a burner and determines whether or not the combustion is abnormal. In this specification, a combustion device mainly applied to a water heater for supplying hot water to a bathtub, hot water to a faucet, or the like will be described as an example.

[0002]

2. Description of the Related Art Conventionally, in a combustion device using gas fuel, a device for detecting the flame current of a burner by flame current detection means including a flame rod in order to determine whether or not abnormal combustion has occurred (Japanese Patent Application Laid-Open No. 59-145422). )It has been known. Further, a device for detecting a fan drive current by a fan drive current detection circuit and a fan rotation speed by a rotation speed detector (JP-A-5-196229) is also known.

[0003]

In the apparatus disclosed in JP-A-59-145422, the normal / abnormal combustion state is determined based on the flame rod (FR) current value and the fan drive current value during burner combustion. Was to be determined. Further, in the apparatus disclosed in Japanese Patent Application Laid-Open No. 5-196229, the degree of adhesion of soot to a heat exchanger or the like is determined based on a fan drive current value and a fan speed during combustion of a burner.

However, in any of the above devices, the FR current detection value which is relatively susceptible to disturbance and whose detection value is unstable and has low detection accuracy, the fan drive current detection value during combustion,
Also, since it was determined whether or not the combustion was abnormal based on the detected value of the number of revolutions of the fan, the reliability of the determination result of the combustion state was low.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a combustion apparatus for detecting the normal / abnormal combustion state of a burner, which can accurately grasp the abnormal combustion state.

[0006]

A combustion apparatus according to the present invention supplies fuel and air to a burner and burns the burner. A plurality of state quantity detection means for detecting a state quantity of the combustion apparatus, and an abnormal combustion state. Judgment mode setting means for setting a specific judgment mode from among a plurality of judgment modes for judging whether the combustion is abnormal or not, based on the detected state quantity, and judging whether or not abnormal combustion occurs according to the set judgment mode And According to this configuration, the determination unit determines whether or not abnormal combustion is performed according to the set determination mode based on the detected state quantity, so that it is possible to perform accurate abnormal combustion determination.

In the combustion apparatus according to a preferred embodiment of the present invention, the plurality of determination modes include a first determination mode for determining whether or not abnormal combustion occurs during burner combustion, and an abnormal combustion during stoppage of burner combustion. And a second judgment mode for judging whether or not this is the case. The combustion device according to this embodiment also includes state quantity selecting means for selecting a state quantity corresponding to the determination mode set by the determination mode setting means from the plurality of detected state quantities.

In the above embodiment, the plurality of state quantity detecting means include a flame current detecting means for detecting a flame current and a fan driving current detecting means for detecting a fan driving current. The determination means determines whether or not abnormal combustion occurs based on the flame current detection value and the fan drive current detection value in the first determination mode, and on the fan drive current value in the second determination mode.

In the first determination mode, when all the state quantity detection values indicate abnormal combustion,
The criterion for determining whether or not the combustion is abnormal in the second determination mode is relaxed. This means that when all the detected state values indicate abnormal combustion in the first determination mode, the probability of actually being abnormal combustion is high. Thus, it is possible to more quickly perform abnormal combustion determination.

[0010] The determining means may determine whether or not the combustion is abnormal, based on the state quantities detected by the plurality of state quantity detecting means and a learning value relating to the secular variation of the detected state quantity. . This makes it possible to perform more accurate abnormal combustion determination.

The determination mode setting means determines that the combustion is abnormal in the first determination mode based on any one of the state quantity detection values, and further determines that the combustion is normal in the second determination mode. The second determination mode is not set until the plurality of state quantity detection values indicate abnormal combustion in the first determination mode. This is because there is a strong possibility that the state quantity is erroneously detected in the first determination mode, and it is useless to execute the second determination mode with such a low-reliability state quantity detection value. is there.

On the other hand, when the determining means determines that abnormal combustion has occurred in all the detected state quantities in the first determining mode, the determining mode setting means immediately sets the second determining mode. In the first determination mode, if all state quantity detection values indicate abnormal combustion, the probability of actually being abnormal combustion is extremely high. In such a case, the second determination mode should be set immediately. It is necessary to make a final determination of the combustion state.

Further, when the determination means determines that the combustion is abnormal in the first determination mode and determines that the combustion is normal in the second determination mode,
Thereafter, the number of times of setting the second determination mode can be reduced. Since the accuracy of the determination as to whether or not the combustion is abnormal is better in the second determination mode, if it is determined that the combustion is normal in the second determination mode, it is determined that the combustion is abnormal in the first determination mode. This is because, even if it is determined, it is not necessary to shift to the second determination mode each time.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing the overall configuration of a combustion apparatus according to one embodiment of the present invention.

The above-described apparatus includes a combustion state monitoring unit 11, an air volume monitoring unit 12, an abnormality determination unit 13, a notification unit 14, a combustion stopping unit 15, a gas amount limiting unit 16, and an air volume increasing unit 17. Prepare. The combustion state monitoring unit 11 monitors the combustion state of the burner (reference numeral 21 in FIG. 2). The air volume monitoring unit 12 monitors the amount of air supplied to the burner 21. The abnormality determination unit 13
Based on the outputs from the combustion state monitoring unit 11 and the air volume monitoring unit 12, the normal / abnormal combustion state of the burner 21 and the cause of the abnormal combustion state of the burner 21 are determined. Notification unit 1
Reference numeral 4 indicates the determination result by the determination unit 13 in a form (image information or audio information) that can be grasped by the user. The combustion stopping unit 15 determines the burner 21 based on the determination result of the determining unit 13.
To stop the combustion operation. The gas amount limiting unit 16 limits the amount of gas fuel supplied from the gas supply source based on the result of the determination by the determining unit 13. The air volume increasing unit 17 increases the amount of air supplied to the burner 21 based on the determination result of the determining unit 13.

The combustion state monitoring unit 11 includes, for example,
Flame current detecting means for detecting the flame current of the burner 21 (=
A flame rod sensor), a CO concentration sensor for detecting the CO concentration of the burner 21, a combustion temperature sensor for detecting the combustion temperature of the burner 21, or an exhaust gas temperature sensor for detecting the temperature of the exhaust gas from the burner 21. You. The air flow monitoring unit 12 includes a fan drive current detection circuit that detects a fan drive current value when the fan rotation speed is a constant value, and a rotation speed detector that detects a fan rotation speed when the fan drive voltage is a constant value. A hot-wire anemometer type or pressure gauge type wind speed sensor is used.

In the above configuration, the combustion state information from the monitoring unit 11 and the air supply amount information from the monitoring unit 12 are both sent to the determination unit 13. In the determination unit 13, these two
If it is determined based on the type information that the combustion state is abnormal and the air supply amount is normal (that is, the air supply amount detection value is larger than a predetermined first threshold value for determining that the air supply amount is insufficient), the acid The combustion operation of the burner 21 is stopped through the combustion stopping unit 15 by determining that the combustion is abnormal due to lack. Then, the determination result and the content of the processing operation are notified to the user from the determination unit 13 through the notification unit 14 simultaneously with the stop of the combustion operation.

Next, based on the above two types of information, when it is determined that the combustion state is abnormal and the air supply amount is insufficient (that is, the air supply amount detection value is smaller than the above-described first threshold value), the determination unit Step 13 checks whether the detected value of the air supply amount is larger than a predetermined second threshold value. Here, the second threshold is for discriminating whether the degree of the air amount shortage is large or small, and is a value smaller than the first threshold. As a result of this check, if it is determined that the air supply amount is larger than the second threshold value, it is determined that the transition to the normal combustion state is possible by increasing the air supply amount, and the determination unit 13
Increases the amount of air supplied to the burner 21 through the air volume increasing unit 17. Also in this case, the determination result and the contents of the processing operation are notified to the user from the determination unit 13 through the notification unit 14 at the same time as the control of increasing the air supply amount is started.

On the other hand, if it is determined that the detected value of the air supply amount is smaller than the second threshold value as a result of the above check, the determination unit 1
3 is to supply gas fuel from the gas supply source to the burner 21 through the gas amount limiting unit 16 in order to judge that it is difficult to shift to the normal combustion state by increasing the air supply amount and to attempt to shift to the normal combustion state by combustion restriction. Let the amount be limited. Also in this case, the determination result and the contents of the processing operation are notified to the user from the determination unit 13 through the notification unit 14 at the same time as the start of the restriction of the gas fuel supply amount.

FIG. 2 is a block diagram showing an example of the configuration of a combustion apparatus in which a flame rod sensor is used for the combustion state monitoring section 11 and a fan drive current detection circuit is used for the air volume monitoring section 12, respectively.

The above device comprises a burner 21 and an insulating member 23.
, The frame rod 24 and the frame rod current (FR
Current) detector 25, AC power supply 26, amplifier 27,
Controller 28, fan 29, fan drive unit 30
And a fan drive current detection circuit 31. Burner 2
1 burns a mixture of air from the outside air suction fan 29 and gas fuel from a gas supply source (not shown) and blows out the flame 22. The flame rod 24 is supported by the insulating member 23 for detecting a flame current, and faces the flame outlet of the burner 21. The AC power supply 26 forms a closed loop together with the frame rod 24, the burner 21 and the like through the flame 22, and supplies power to the closed loop. FR current detector 25
Constitutes a flame rod sensor (= flame current detecting means) together with the frame rod 24, is connected to this closed loop, and detects and outputs an FR current flowing through this closed loop. In the following description, the description about the frame rod sensor is represented by the FR current detector 25 unless otherwise specified. The amplifier 27 is connected to the detector 25
The output signal from is amplified and output. The fan 29 is driven by the fan drive unit 30. The fan drive current detection circuit 31 detects a fan drive current flowing through the fan drive unit 30 and outputs the same to the controller 28. The controller 28 performs predetermined arithmetic processing operations (each processing operation indicated by reference numerals 13 to 17 in FIG. 1) based on the output from the amplifier 27 and the output from the current detection circuit 31.

The controller 28 compares the output from the amplifier 27 with a threshold value a 'in a table of FR current-CO concentration characteristics stored in advance (see FIG. 3: determined for each number of combustion amounts). Based on the result of the comparison, it is determined whether or not the combustion state is abnormal, and the combustion of the burner 21 is stopped or the combustion amount is limited. This threshold value a 'is the value of C at which abnormal combustion is determined.
This is the FR current value corresponding to the O concentration value a (for example, 1000 ppm).

The FR current-CO concentration characteristic curve shown in FIG. 3 is for judging abnormal combustion caused by an increase in CO concentration (ie, lack of oxygen).

The controller 28 outputs the output from the current detection circuit 31 and a table of the fan drive current-air amount characteristic stored in advance (see FIG. 4: determined for each number of combustion amounts).
Are compared with the threshold values b ′ and c ′. Then, based on the comparison result and the comparison result between the FR current and the threshold value a ′,
The determination of oxygen deficiency, insufficient air amount “medium”, and insufficient air amount “large” is made (see FIG. 6).

FIG. 5 shows the sequence of the processing operation for the above-mentioned determination by the controller 28, and FIG. 6 shows the details of the processing, respectively.

FIG. 4 is a table showing fan driving current-air amount characteristics when the rotation speed of the fan 29 is constant. This table shows not only the relationship between the fan driving current value and the air amount, but also The relationship between these and the CO concentration value is also shown. That is, the table clearly shows that when the fan drive current value (fan rotation speed) increases, the amount of air flowing into the burner 21 increases, and conversely, the CO concentration decreases.

In FIG. 4, a symbol b 'indicates a CO concentration value b (for example, 10%) for judging normal combustion or abnormal combustion.
00 ppm). This value b 'is a threshold value (the above-described first threshold value) for determining whether the air supply amount to the burner 21 is normal or abnormal. The symbol c 'is a CO concentration value c (for example, 2000 ppm) for determining whether the degree of abnormal combustion is large or small.
Is a fan drive current value corresponding to. That is, this value c 'is a threshold value (the above-described second threshold value) for determining whether the degree of the shortage of the air supply amount is large or small.

Next, a first example of a processing flow when the controller 28 determines whether or not abnormal combustion is performed will be described.
This will be described with reference to the flowchart of FIG.

First, it is checked whether or not the FR current value detected by the combustion state monitoring unit 11 (ie, the FR current detector 25) is smaller than the threshold value a 'in FIG. (Step S1). At this stage, it is unclear whether the cause of the abnormal combustion is due to lack of oxygen or air shortage for the reasons described above. Next, it is checked whether or not the air amount detected by the air amount monitoring unit 12 is smaller than a first threshold value b '(step S).
2). As a result, if it is determined that it is not small (that is, the air amount is normal), it is determined that the cause of the abnormal combustion is “oxygen deficiency” (the determination result indicated by the symbol in FIG. 6) (step S3), and the safety of the user or the like is secured Immediately, the combustion is stopped (step S4). Then, the user is warned of abnormal combustion due to lack of oxygen in a predetermined manner (image information, audio information, buzzer, or the like) (step S5).

On the other hand, if it is determined that the detected air amount is smaller than the first threshold value b '(that is, the air amount is insufficient) (steps S2 and S6), then it is determined whether the air amount is smaller than the second threshold value c'. Is checked (step S7). As a result,
When it is determined that the air amount is not small (that is, the air amount is insufficient, the result of determination is indicated by the reference numeral in FIG. 6), it is determined that the transition to normal combustion is possible by eliminating the air amount insufficiency, and the fan drive unit 30 is activated. By controlling, the air supply amount to the burner 21 is increased (step S8).

If it is determined that the detected air amount is smaller than the second threshold value c '(determination result indicated by reference numeral in FIG. 6) (step S7), the air supply filter is clogged or the soot of the heat exchanger is removed. It is supposed that the air introduction part is extremely blocked, such as clogging, and the degree of air shortage has increased. Therefore, it is determined that it is difficult to solve the shortage of the air amount due to the increase in the number of rotations of the fan.
The amount of gas fuel supplied to the burner 21 is controlled so that the amount of combustion of the burner 21 matches the amount of air supplied (step S).
9). Then, the amount of combustion is limited (for example, the number of combustion is 20
That the burning operation of the burner 21 is continued in a state where the number is reduced from No. 10 to No. 10 in a form such as image information or audio information that can be grasped by the user (step S1).
0).

If it is determined in step S1 that the FR current value is larger than the threshold value a 'in FIG. 3, there is no problem since it is "normal combustion" (determination result indicated by reference numeral in FIG. 6).

As described above, according to one embodiment of the present invention, it is possible to determine whether the cause of abnormal combustion is due to lack of oxygen or to a shortage of air. Then, the combustion is immediately stopped, so that sufficient safety for the user can be ensured. Also,
When it is determined that the abnormal combustion is due to the shortage of the air amount, it is possible to grasp whether the degree of the shortage of the air amount is large or small, and when the degree of the shortage of the air amount is small, the normal combustion is performed by increasing the air supply amount to the burner 21. Is possible,
Usability is improved. On the other hand, when the degree of the shortage of the air amount is large, the supply amount of the gas fuel to the burner 21 is limited, and the combustion amount of the burner 21 is controlled so as to match the air supply amount. Since the combustion operation of the above can be continued, the usability is also improved. When the combustion is stopped due to lack of oxygen, a warning is issued to the user, and the combustion operation of the burner 21 is continued in a state where the amount of combustion is restricted due to a large degree of insufficient air amount. In such a case, the user is notified to that effect, so that the user can easily grasp the cause of the stop of combustion and the restriction of combustion.

By the way, the above-described operation of judging whether or not the combustion state is abnormal includes the fact that the combustion device is relatively susceptible to disturbances, the detection value is unstable, the detection current is low, and the detection accuracy is low. Since it is performed based on the drive current value,
The reliability of the judgment result is not so high. Then, the following method can be considered as a means for improving the reliability of the determination result. In other words, during combustion, a tentative judgment is made based on the two detected values, and if the result is "abnormal", the fan drive current value is set higher during post-purge after the end of combustion, so that the fan drive current value is increased. Is performed, and the detection accuracy is also improved to perform the highly reliable main determination. However, if the fan rotation speed is increased to increase the reliability of the detected value of the fan drive current, the temperature of the heat exchanger and the combustion chamber will be reduced more than necessary, and the tapping performance and combustion performance at the time of re-ignition. It is not preferable because it causes the deterioration of.

Therefore, in the processing flows shown in FIGS. 7 and 8, in any case, the temporary determination mode is unconditionally set during the combustion. However, the temporary determination mode is switched from the temporary determination mode to the main determination mode at the end of the combustion. At the time of migration, it was decided to eliminate the above-mentioned inconvenience by subjecting the system to certain restrictions.

FIG. 7 is a flowchart showing a second example of the processing flow when the controller 28 makes an abnormality determination.

In the processing flow shown in FIG. 7, during combustion, a temporary determination as to whether or not the combustion is abnormal is always made based on the FR current detection value and the fan drive current detection value. As a result, one of the detection values becomes abnormal. In this case, the main determination is made again based on the detected value of the fan drive current at the end of combustion. However, as a result of this determination, when there is no abnormality, except for the case where both of the above detection values indicate abnormality and the case where one of the detection values shows abnormality and the other shows a value close to abnormality after the next time. It does not shift to this judgment. Hereinafter, a second example of the processing flow by the controller 28 will be described with reference to FIG.

In FIG. 7, the controller 28 is in the temporary determination mode during the combustion of the combustion device.
Based on the FR current detection value read from the detector 25, it is provisionally determined whether or not the combustion is abnormal (step S11). If the result of the tentative determination is “abnormal”, a memory (not shown) in the controller 28 is used to make a final determination of the combustion state of the combustion device based on the detected value of the fan drive current at the time of post-purging after the end of combustion. Is set to "1" in the final determination request code field set in (step S12).

Next, based on the fan drive current detection value read from the current detection circuit 31, it is provisionally determined whether or not abnormal combustion (abnormal combustion due to blockage of a heat exchanger or the like) occurs (step S1).
3). As a result of the provisional determination, if it is recognized as "abnormal", "2" is set in the above-described final determination request code column to perform the final determination at the time of post-purging (step S1).
5).

In this case, both "1" and "2" are set in the final determination request code column (step S1).
6) After the completion of combustion, the mode shifts to the main determination mode when the mode shifts to the post-purge, and the main determination operation of the combustion state based on the detected value of the fan drive current is executed (step S17). This final determination operation is performed by the fan 29
In a state where the fan drive current value is rotated at a higher speed than at the time of normal post-purge, and the fan drive current value is hardly affected by disturbance such as wind, so that the accuracy of detecting abnormal combustion (= reliability) by the fan drive current value is increased. This means determining the degree of blockage of the supply / exhaust system. That is, since this determination operation is performed during non-combustion of the combustion device, the abnormal combustion is not directly detected, but whether the next or subsequent combustion becomes abnormal combustion is determined based on the degree of blockage of the heat exchanger or the like. Is indirectly determined.

If it is determined in this determination that the combustion is not abnormal, the determination request codes "1" and "2" set in steps S12 and S15 are cleared, and a series of abnormality determination operations are terminated (step S18). , S19).

On the other hand, if it is determined in this determination that the combustion is abnormal, the above-described determination request code is cleared, and
After taking measures for abnormal combustion, a series of abnormal determination operations are terminated (steps S18, S20, S21).

Next, when it is tentatively determined that the combustion is not abnormal based on the FR current detection value read from the detector 25 (step S11), the abnormal combustion is detected based on the fan drive current detection value read from the current detection circuit 31. It is temporarily determined whether or not combustion has occurred (step S13). When it is determined that the state is "abnormal", "2" is set in the main determination request code column (step S15), and only "2" is set in the main determination request code column. Or not,
At the time of post-purging, it is checked whether it is possible to shift to the main determination (steps S16 and S22). Here, the main determination limit mode is a mode in which one of the two detection values is provisionally determined to be “abnormal” and the main determination is performed based on the fan drive current detection value. This is a mode for temporarily determining that both of the detection values are “abnormal”, or restricting this determination only when one is “abnormal” and the other is close to abnormal.

As a result of this check, if it is determined that the mode is not in the main determination limit mode, the mode is shifted to the main determination mode at the time of transition to post-purge after the end of combustion, and the main determination operation is executed (step S23). ). If it is determined in this main determination that the combustion is not abnormal, the main determination request code "2" set in step S15 is cleared, the main determination limit mode is set, and a series of abnormality determination operations are terminated (step S28). , S29).

Here, if the main determination limit mode is set in step S22, it indicates that the FR current detection value is normal and that the result of the main determination indicates that the combustion is not abnormal. . In other words, in the provisional determination, the fan drive current detection value is affected by disturbance or the fan drive current detection value varies, so that such a low reliability fan drive current detection value Since it is useless to make a main determination based on the main determination, the main determination restriction mode is set. As described later, the same applies to the case where the fan drive current detection value is normal and the FR current detection value is abnormal in the tentative determination.

On the other hand, if it is determined in this determination that the combustion is abnormal, the above-described determination request code is cleared, and
After taking measures for abnormal combustion, a series of abnormality determination operations are terminated (steps S24, S25, S26). When it is determined in step S22 that the present determination restriction mode is in effect, the final determination request code "2" set in step S15 is cleared, and a series of abnormality determination operations is terminated (step S27).

The processing flow of steps S16 and S22 to S29 is as follows. In step S11, the detected value of the FR current is determined to be abnormal, and in step S12, this determination request code is set to "1". The same operation is performed when it is determined that the current detection value is not abnormal and the process proceeds to step S16 via step S14. If neither the FR current detection value nor the fan drive current detection value is abnormal (steps S11 and S13), the determination request code is not set (step S1).
4), do not shift to the main determination.

The reason why the detected value of the fan drive current is used in this determination is that the post-purge can fix the fan rotation speed to an arbitrary rotation speed for a predetermined time, unlike during combustion, so that the fan drive current detection value is used. This is because the detection accuracy of the value is good and the detection value is stable.

As described above, according to the processing flow shown in FIG. 7, when one of the FR current detection value and the fan drive current detection value is provisionally determined to be “abnormal” during combustion, the post-combustion post-combustion state is determined. In the purging, the main determination is made based on the detected value of the fan drive current, and as a result, when there is no abnormality, the transition to the main determination is restricted from the next time.
For this reason, the number of times of the main determination can be reduced, and at the time of re-ignition due to a decrease in the temperature of the heat exchanger and the combustion chamber by setting the fan rotation speed to a higher speed than at the time of normal post-purging at the time of the main determination. It is possible to minimize a decrease in tapping performance and combustion performance, and to minimize the generation of noise.

FIG. 8 is a flowchart showing a third example of the processing flow when the controller 28 makes an abnormality determination.

The process flow shown in FIG. 8 is for the case where a temporary judgment is made as to whether or not abnormal combustion is to be performed only based on the detected value of the FR current, and then the main judgment is made based on the detected value of the fan drive current. Is unconditionally set to the temporary determination mode, but the transition from the temporary determination mode to the main determination mode at the end of combustion is still subject to certain restrictions. That is, during combustion, F
A temporary determination as to whether or not abnormal combustion is made is always made based only on the R current detection value. As a result, when it is determined that the combustion is abnormal, the main determination is made again based on the fan drive current detection value at the end of combustion. However, as a result of this final determination, if it is not abnormal, the final determination limited mode will be set, and from the next time onward, even if it is determined that the temporary determination is abnormal, unless the final determination limited mode is released, Does not shift to this determination. Hereinafter, a third example of the above processing flow by the controller 28 will be described with reference to FIG.

In FIG. 8, as in FIG. 7,
During the combustion of the combustion device, the temporary determination mode is set. First,
Based on the FR current detection value read from the detector 25, it is provisionally determined whether or not the combustion is abnormal (step S31). If it is determined as “abnormal” as a result of the provisional determination, the final determination restriction mode (=
It is checked whether it is during the main determination limit mode in FIG. 7 (that is, whether it is possible to shift to the main determination based on the detected value of the fan drive current at the time of post-purging, as in FIG. 7) (step S32). As a result of this check, if it is determined that the present determination restriction mode is not in effect, the combustion mode is shifted to the main determination mode at the time of transition to post-purge after the end of combustion, and the main determination operation is executed (step S41).

Then, as a result of the main judgment, it is checked whether or not the degree of blockage of the heat exchanger or the like has progressed from the time of the previous main judgment (step S42). As a result, if it is determined that progress is being made, measures are taken against abnormal combustion due to blockage of the heat exchanger or the like (step S43), and this determination operation ends. If it is determined in step S42 that the vehicle has not progressed, the same FR as in step S31 is used.
The main determination limit mode is set in order to prevent the use of the current detection value from shifting to the useless main determination again. That is,
Although the FR current detection value is affected by disturbance such as dust and is not actually abnormal combustion, the reliability of the controller 28 is so low that it is erroneously determined to be abnormal combustion. (Step S
44).

On the other hand, after tentatively determining abnormal combustion based on the detected value of FR current (step S31), if it is determined that the main determination limit mode is being executed (step S32), the main determination limit counter in the controller 28 (not shown). ) Is incremented (step S33). Then, it is checked whether or not the count value of the main determination limit counter has reached 10 (step S34). If it is determined that the count value has reached 10, the main determination limit counter is cleared (step S35). The mode is released (step S36). Next, as in step S41, the main determination operation is performed (step S37).

Then, as in step S42, it is checked whether or not the degree of blockage of the heat exchanger or the like has progressed since the last main determination (step S38). As in step S43, measures are taken for abnormal combustion due to blockage of the heat exchanger or the like (step S39). After that, the main determination operation ends. If it is determined in step S38 that the vehicle is not progressing, the main control section sets the main determination restriction mode as in step S44 (step S40). If it is determined in step S31 that the combustion is not abnormal combustion based on the detected FR current value, the process does not shift to the present determination operation.

As described above, according to the processing flow shown in FIG. 8, when the FR current detection value is provisionally determined to be “abnormal” during combustion, the post-purge after the combustion is completed based on the fan drive current detection value. The main determination is performed, and as a result, when there is no abnormality, the transition to the main determination is restricted from the next time until the main determination mode is canceled. For this reason, the number of times of the main determination can be reduced, so that a decrease in the tapping performance or the combustion performance at the time of re-ignition due to a decrease in the temperature of the heat exchanger or the combustion chamber caused by performing the main determination frequently is minimized. Noise can be minimized, and noise generation can be minimized.

It should be noted that the above description relates only to the embodiment of the present invention and does not mean that the present invention is limited to only the above described content.

For example, when the FR current detection value and the fan drive current detection value are both "abnormal" in the tentative determination, it is determined in this determination whether the fan drive current detection value is "abnormal". The threshold can also be relaxed. This is because the disturbance factors that affect the FR current value and the fan drive current value during combustion are often different, so that the FR current detector 25 and the fan drive current detection circuit 31
If both of them detect an abnormal value, it is extremely likely that abnormal combustion actually occurs. Therefore, in such a case, by relaxing the threshold value of the fan drive current value, the controller 28 can quickly perform the “abnormal” determination. In this modification, a temporary determination is made only with the FR current detection value, and when “abnormal” is determined, the threshold for determining whether the fan drive current detection value is “abnormal” in the main determination is relaxed. You can also. This is because, when all the detection values (in this case, only the FR current detection value) are “abnormal” in the tentative determination, the probability that the combustion state is abnormal is relatively high. This is because when the value is “abnormal”, it is possible to quickly determine that the combustion state is “abnormal” in this determination.

In addition, the transition of the combustion state over time with respect to the FR current value and the fan drive current value is learned in advance, and when the "abnormal" combustion state is determined by actually performing a tentative determination, the learned value is determined. If it is determined from the result of comparison with the detected abnormal value that the reliability of the detected value is extremely high, the threshold value of the fan drive current value can be relaxed in this determination.
This is an “abnormal” condition if the FR current value and the fan drive current value are continuously monitored for changes in combustion state over time.
Is detected, it is possible to determine whether the cause is due to the gradual blockage of the heat exchanger or due to disturbance, and the reliability can be improved.

In the tentative judgment, when both detected values show values close to "abnormal", the main judgment can be made at that time. In the tentative determination, the detection accuracy of both the FR current value and the fan drive current value is poor, and the variation in the detected values is large. Therefore, if both detected values are close to "abnormal", the combustion state is likely to be "abnormal" or a state close to it. This is to advance the timing of performing the determination.

Further, in the tentative judgment, both the detected values are "abnormal" or one of the detected values is "abnormal", and the fan drive current detected value at the time of the tentative judgment and the main judgment were made. If there is a large difference from the detected value of the fan drive current at that time, the timing of the main determination after the next time can be changed. In this case, the current detector 25 and the current detection circuit 31 in the tentative determination are in a state where they are likely to be erroneously detected due to some external factor. So after that,
Since it is not necessary to make a main determination having a great disadvantage when the erroneous detection is performed in the tentative determination, the main determination is performed once every time the abnormality is detected several times in the tentative determination.

[0063]

As described above, according to the present invention,
In a combustion device for detecting a normal / abnormal combustion state of a burner, it is possible to provide a combustion apparatus capable of accurately grasping a combustion state abnormality.

[Brief description of the drawings]

FIG. 1 is a block diagram of a combustion device according to an embodiment of the present invention.

FIG. 2 is a block diagram when an FR current detector and a fan drive current detection circuit are employed in the apparatus of FIG. 1;

FIG. 3 is a diagram showing an FR current-CO concentration characteristic of a frame rod.

FIG. 4 is a diagram showing a fan drive current-air amount characteristic of the fan drive current detection circuit.

FIG. 5 is a flowchart illustrating a first example of a processing flow by a controller (an abnormality determination unit).

FIG. 6 is an explanatory diagram of decision logic obtained as a result of the processing flow of FIG. 5;

FIG. 7 is a flowchart showing a second example of the processing flow by the controller.

FIG. 8 is a flowchart showing a third example of the processing flow by the controller.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Combustion state monitoring part 12 Air volume monitoring part 13 Abnormality judgment part 14 Notification part 15 Combustion stopping part 16 Gas amount restriction part 17 Air volume increasing part 21 Burner 23 Insulation member 24 Frame rod 25 FR current detector 26 AC power supply 27 Amplifier 28 Controller 29 Fan 30 Fan drive unit 31 Fan drive current detection circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuaki Baba 43-1, Uozakihama-cho, Higashinada-ku, Kobe, Hyogo Prefecture Within Nihon Yupro Corporation (72) Inventor Hiroshi Munemura 43, Uozakihama-cho, Higashinada-ku, Kobe-shi, Hyogo No. 1 Inside Nippon Yupro Co., Ltd. (72) Inventor Shigeo Yoshida 43-1, Uozakihama-cho, Higashinada-ku, Kobe City, Hyogo Prefecture Inside Nippon Yupro Co., Ltd.

Claims (10)

[Claims] 1. A combustion apparatus for supplying fuel and air to a burner for combustion, wherein a plurality of state quantity detecting means for detecting a state quantity of the combustion apparatus, and a plurality of judgments for judging whether or not the combustion is abnormal. A determination mode setting unit that sets a specific determination mode from among the modes, and a determination unit that determines whether or not abnormal combustion is performed according to the set determination mode based on the detected state amount. Burning device. 2. The combustion apparatus according to claim 1, wherein the plurality of determination modes are a first determination mode for determining whether or not abnormal combustion is occurring during the combustion of the burner, and an abnormality is determined while the combustion of the burner is stopped. A second determination mode for determining whether or not combustion has occurred. 3. The combustion apparatus according to claim 1, further comprising a state quantity selecting unit that selects a state quantity corresponding to the determination mode set by the determination mode setting unit from the plurality of detected state quantities. A combustion device characterized by the above-mentioned. 4. The combustion apparatus according to claim 1, wherein the plurality of state quantity detection means includes a flame current detection means for detecting a flame current, and a fan drive current detection means for detecting a fan drive current. Features combustion equipment. 5. The combustion device according to claim 1, wherein the determination unit is configured to detect a flame current and a fan drive current in the first determination mode.
In the determination mode of (1), it is determined whether or not the combustion is abnormal, based on the fan drive current value. 6. The combustion device according to claim 2, wherein in the first determination mode, when all of the state quantity detection values indicate abnormal combustion,
A criterion for deciding whether or not the combustion is abnormal in the determination mode. 7. The combustion device according to claim 1, wherein the determination means is based on a state quantity detected by the plurality of state quantity detection means and a learning value related to a secular variation of the state quantity detection value. A combustion device for determining whether or not the combustion is abnormal. 8. The combustion device according to claim 2, wherein the determination mode setting means determines that the combustion is abnormal by the one of the state quantity detection values in the first determination mode. When it is determined that the normal combustion is performed in the second determination mode, the second determination mode is not set until the plurality of state quantity detection values indicate abnormal combustion in the first and subsequent determination modes. A combustion device characterized by the above-mentioned. 9. The combustion apparatus according to claim 1, wherein the determination mode setting means immediately determines the abnormal combustion when the determination means determines that abnormal combustion has occurred in the first determination mode based on all the state quantity detection values. 2. A combustion apparatus, wherein a determination mode of 2 is set. 10. The combustion apparatus according to claim 1, wherein the determination mode setting means determines that the combustion is abnormal in the first determination mode and the second determination mode.
When it is determined in the determination mode that the combustion is normal, the number of times of setting the second determination mode is reduced thereafter.