JP3302542B2 - Abnormal combustion judgment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for judging abnormal combustion in combustion equipment such as a water heater.

[0002]

2. Description of the Related Art Like a water heater, a required amount of heat for obtaining a set temperature of a hot water is calculated based on a state quantity of flowing water such as a tap water temperature, and an air supply device and a fuel supply are calculated in accordance with the required amount of heat. 2. Description of the Related Art Combustion devices for controlling a supply device and the like are known. In such a combustion device, a device that detects abnormal combustion by detecting a flame current and comparing it with a reference value is disclosed in
It is publicly known as shown in -184340.

[0003]

Some types of combustion equipment, for example, water heaters, are used for a wide range of applications, from large-flow showers to small-flow kitchen water heaters. Even when the width is large and the faucet opening is kept constant, the required combustion amount also fluctuates due to fluctuations in water flow due to fluctuations in the original water pressure. For this reason, the conventional abnormal combustion detection device has a problem that a large change in the combustion state due to a change in the combustion amount prevents accurate abnormal combustion determination.

Accordingly, it is an object of the present invention to provide a device for detecting abnormal combustion in a combustion apparatus, which minimizes the influence of fluctuations in the combustion state due to fluctuations in the amount of combustion, thereby enabling accurate abnormality judgment.

[0005]

An abnormal combustion judging device according to a first aspect of the present invention is for a combustion device for controlling an air supply amount and a fuel supply amount according to a required combustion amount. Detecting means for detecting a predetermined state quantity at the time of combustion, and eligibility for judging whether the state quantity detected by the detecting means satisfies a predetermined eligibility condition indicating that the state quantity is eligible for use in abnormality determination. A determination unit; and an abnormality determination unit configured to determine whether there is an abnormality based on the detected state quantity when the eligibility determination unit determines that the eligibility condition is satisfied.

Here, the predetermined state quantity may be, for example, a flame current for the combustion state, an oxygen amount, an exhaust temperature, or the like. Further, a value calculated in the control of the combustion state, for example, In the water heater, the water flow rate is Q, the incoming water temperature is Tc, the set hot water temperature is Ts, and the outlet water temperature is
h, when the function of the PID calculation is fPID, Q (Ts−T
c) + fPID (Ts-Th) and the ratio or difference between Q (Th-Tc) and the like can also be adopted. Further, as the state quantity related to the air supply, a drive current value to the fan motor, an air flow rate, or the like can be adopted. Then, when such a state quantity is out of a predetermined normal range, for example, it can be determined that an abnormality has occurred.

According to the abnormal combustion judging device of the present invention, it is judged whether or not the state quantity is suitable for use in judging an abnormality at the time of combustion of the device, and when the device is eligible, the abnormality judgment is made.
Accurate determination is possible.

[0008] In addition to the above configuration, the abnormal combustion judging device according to the first aspect of the present invention further includes the step of, when the required combustion amount exceeds the maximum combustion amount of the combustion equipment, the required combustion amount. There is also provided combustion amount limiting means for limiting the combustion amount to the maximum.

[0009] When the combustion amount limiting means limits the required combustion amount to the maximum combustion amount, the abnormality judging means considers that one of the qualification conditions is satisfied.

An abnormal combustion judging device according to a second aspect of the present invention is for a combustion device that controls an air supply amount and a fuel supply amount according to a required combustion amount, and determines a predetermined state quantity of the combustion device. Detecting means for detecting; eligibility judging means for judging whether the state quantity detected by the detecting means satisfies a predetermined eligibility condition indicating that the state quantity is eligible for use for abnormality determination; and When the means determines that the eligibility condition is satisfied, an abnormality determining means for determining whether or not there is an abnormality based on the detected state quantity, so as to achieve an intended use of the combustion equipment. First control means for controlling the air supply amount or the fuel supply amount;
A second control unit that controls the air supply amount or the fuel supply amount in a predetermined state in which the state quantity changes little, and a selection unit that selects one of the first and second control units. One of the eligibility conditions is that the second control means is selected. That is, when the second control means is selected, the state quantity is considered to be stable, and it is determined that the eligibility condition is satisfied.

[0011] If the first control means and the second control means are provided so as to be selectable as described above, the combustion equipment is controlled by the first control means so as to meet a user's request in a certain situation. In another case, the combustion device can be controlled to a state suitable for abnormality determination by the second control means, and as a whole, the user's request is satisfied,
It is possible to balance safety with accurate abnormality determination.

In a preferred embodiment, this two is used for judging the abnormality of the air supply fan in pre-purge and post-purge.
It adopts a system with two control means. That is, the first control means sets the fan rotation speed or the rotation time in the pre-purge and post-purge to a relatively low first rotation speed suitable for the purpose of the pre-purge and post-purge (for example, close to the fan rotation speed at the time of ignition). Value) or a relatively short first time. On the other hand, the second control means controls the fan rotation speed or the rotation time in the pre-purge and the post-purge to a sufficiently high second rotation speed or a sufficiently long second time.

As a result, when the second control means is selected, a highly accurate abnormality determination can be performed in a state where the influence of noise in the fan control is small. On the other hand, when the first control means is selected, for example, for the pre-purge, the pre-purge is completed in a short time, the fan speed is immediately shifted to the speed at the time of ignition, and the ignition operation is immediately started. Therefore, it is possible to quickly satisfy the user's request.

[0014] In this case, particularly in the case of a water heater, it is desirable that the first control means be selected in a usage mode in which the tapping water is directly in contact with the user as in general hot water supply, in order to give the user a pleasant feeling. On the other hand, the second usage mode is desirably selected in a usage mode in which the hot water is not directly touched by the user, such as hot water filling or reheating, so as not to give the user any discomfort.

In a preferred embodiment, the method using the above two control means is adopted for the determination of abnormality of the combustion state. That is, the first control means controls the air supply amount and the fuel supply amount so as to burn at a required combustion amount, and the second control means controls the air supply amount and the fuel supply amount so as to burn at a constant combustion amount. Controlling the amount. When the second control means is selected, fluctuations in the combustion state are reduced, so that a highly accurate abnormality determination can be made.

In this case, as a method of selecting the first and second control means, for example, when the control by the first control means enters a steady state, the second control means is replaced by the second control means. Can be selected. This makes it possible to perform constant combustion amount control suitable for abnormality determination while substantially maintaining control in accordance with the user's request. In this case, when the set value and other conditions change and the constant combustion amount control no longer meets the user's request, returning to the first control again substantially reduces the user's request. Desirable to always meet.

Further, as another selection method, for example, it is determined whether or not the possibility of occurrence of an abnormality is high under predetermined conditions,
When the possibility of occurrence of abnormality is high, the second control means can be selected. Here, when the possibility of occurrence of an abnormality is high, for example, when the use time or the number of uses of the device is increased by a certain step amount, or when a certain state amount is out of a normal range can be adopted. In particular, when it is determined that the possibility of occurrence of an abnormality is high when the usage time and the number of times of use of the device are increased by a certain step amount, by reducing the step amount as the usage time and the number of times of use increase,
It is desirable that abnormality determination is performed at shorter intervals for older devices.

[0018]

FIG. 1 shows the overall configuration of an embodiment of a water heater to which the present invention is applied.

First, a hot water piping system will be described. The general hot water supply pipe includes a water inlet pipe 5, a hot water supply heat exchanger 3, and a tapping pipe 6. The tapping pipe 6 is connected at its tip to a faucet 7 of a kitchen or bath. The inlet pipe 5 is provided with sensors for the incoming water flow rate Q and the incoming water temperature Tc, and the outlet of the hot water supply heat exchanger 3 is provided with a sensor for the outlet water temperature Th.

The outlet of the hot water supply heat exchanger 3 is also connected to the hot water pipe 2, which is connected to a circulation pipe 9 for bath.
Is connected. The filling pipe 2 is provided with an opening / closing valve for turning on / off the filling and a sensor for the filling quantity Qf.

The circulation pipe 9 for the bath is a pipe in which the bathtub 8 and the heat exchanger 4 for reheating are connected to a loop, and includes a circulation pump 10 for generating a circulation flow at the time of reheating. A bath temperature Tf sensor is provided near the bathtub-side entrance of the circulation pipe 9.

The heat exchanger 3 for hot water supply and the heat exchanger 4 for additional heating are combined into a one-can, two-water type integrated heat exchanger 2.

Next, the combustion system will be described. Two burners 11 and 12 are provided for the integrated heat exchanger 2, and one of the burners 11 is provided with a flame (frame) current If detection unit 18. On-off valves 13 and 14 for combustion on / off are provided in the fuel supply pipes of the burners 11 and 12 respectively.
Is provided. Further, a proportional valve 15 for adjusting the combustion amount is provided in the fuel supply source pipe.

Further, a fan 16 for supplying combustion air to the burners 11 and 12 is provided. The fan 16 has a fan motor current (fan current) Ifa
A detection unit for n and the fan speed NR is attached.

Finally, the control system will be described. Control unit 30
Is composed of, for example, a microcomputer and attached peripheral circuits. The control unit 30 includes a tapping temperature setting unit 32, a bath temperature setting unit 33, a hot water filling amount setting unit 34, a reheating switch 31,
A set value and an operation command are received from the hot water switch 35 and the like, and detection values are input from various sensors and detection units in the above-described hot water piping system and the combustion system, and control processing described later is performed. The control process includes a process for controlling the operation of the water heater and a process for detecting an abnormality in the combustion state, and the above-described on-off valve and proportional valve according to the processing results. , Pumps, fans, etc. are controlled,
When an abnormality occurs, a warning display is output to the warning display unit 36.

Hereinafter, control processing performed by the control unit 30 will be described.

FIG. 2 shows a routine for integrating the use time and the number of times the water heater is used. When the change of the burner from the extinguishing state to the igniting state is detected based on the frame current If (S
1) The use time timer is started (S2), and the use time until the fire extinguishing state is detected again (S3) is measured. Then, the measured use time is added to the use time integrated value stored in the memory (S4), and the use count integrated value stored in the memory is increased by one (S4).
5).

By performing the above operation each time combustion is performed, an integrated value of the past use time and the number of times of use of this water heater can be obtained. This integrated value is used to determine whether the possibility of occurrence of abnormality is high or low in a combustion sequence described later.

FIGS. 3 to 6 show a combustion routine for controlling the combustion operation of the water heater.

First, as shown in FIG. 3, it is checked whether or not there is a combustion request (S11). That is, when the water flow rate Q is greater than 0 (= the faucet is opened), the hot water switch 35 is turned on,
Alternatively, if either the additional heating switch 31 is turned on, it is determined that there is a combustion request.

When it is determined that there is a combustion request, first, the abnormality occurrence low mode is initially set (S12), and then the usage time integrated value is greater than a predetermined reference time (for example, 10 hours) (S13), or It is checked whether the number-of-times integrated value is larger than a predetermined number (S14). As a result, S12, S13
If the check result is NO, it is checked whether or not the general hot water supply is used (that is, whether or not the flow rate Q is larger than the filling rate Qf) (S15). as a result,
If it is determined that general hot water supply is not being performed, that is, it is determined that only hot water filling or additional heating is being performed, the prepurge rotation speed is set to a sufficiently high rotation speed (for example, 4000 r.
pm), the prepurge timer is set to a sufficiently long time (for example, 10 seconds) (S19), and the fan is driven for the set time at the sufficiently high set rotation speed to perform prepurge (S20, 23). During the prepurge, after the fan drive current Ifan is stabilized (S21), it is checked whether the fan drive current Ifan is smaller than a predetermined reference value (S22). A warning is displayed by making a judgment (S23, S2
4).

The reason why the fan is driven at a sufficiently high rotation speed is that the higher the rotation speed is, the lower the influence of the resolution of the rotation speed control is, and the more accurate the abnormality determination can be made. For example, the controllable rotational speed resolution is 50r
pm, the effect of this resolution is 500 rpm.
rpm is 10%, while the number of rotations is 500
For 0 rpm, it is reduced to 1%. The reason why the abnormality determination is performed after the fan drive current is stabilized is that highly accurate determination cannot be expected in a transient state. In addition, a sufficiently long pre-purge time is taken to stabilize the fan drive current, and the ignition is delayed by that much, and hot water at a temperature lower than the set temperature comes out. Since the user is not touched, there is no problem that the user feels uncomfortable.

On the other hand, when the general hot water supply is used in step S15, the pre-purge rotation speed is set to a rotation speed slightly higher than the rotation speed at the time of ignition (for example, 2000 rpm), and the pre-purge timer is set to the shortest that can achieve the pre-purge function. (For example, 0.5 seconds) (S16), and the fan is driven at the low rotation speed for the shortest time to perform the prepurge (S17, 18).

Here, in the case of general hot water supply, the reason why the pre-purge is performed with the fan rotation speed close to the time of ignition and the shortest time is that in the general hot water supply, the hot water is directly in contact with the user, so that the pre-purge can be completed in a short time as possible. This is because, by shifting to the ignition operation as soon as possible, hot water at the set temperature is quickly supplied from opening to give the user a comfortable feeling.
In this case, since the pre-purge time is very short and the fan drive current is not stable, the abnormality check based on the fan drive current cannot be performed accurately, so that the description is omitted.

The determination as to whether or not the general hot water supply is used in step S15 may be made based on the magnitude of the set temperature Ts. For example, when the set temperature Ts is extremely high, for example, at 75 ° C., such a high temperature is not used in the ordinary hot water supply, and it can be determined that the general hot water supply is not performed.

Further, if it is determined in the checks in steps S13 and S14 that either the usage time integrated value or the usage count integrated value is larger than the predetermined time or the predetermined number of times, the usage time integrated value or the usage count integrated value is determined. After once resetting to zero (S25), the predetermined time and the predetermined number of times are reset to values smaller than the previous values (S26), the abnormality occurrence high probability mode is set (S27), and the process proceeds to step S19. In advance, irrespective of whether general hot water is included or not, pre-purge is performed for a sufficient time at a sufficiently high fan speed, and an abnormality check is also performed. By this processing, an abnormality check is always performed every time the usage time integrated value or the usage count integrated value exceeds a predetermined value. That is, the abnormality check is always performed at a certain frequency or higher. In addition, in step S26, as the water heater becomes older (in other words, the possibility of occurrence of abnormality increases), the frequency of performing the abnormality check increases (that is, the abnormality check is performed) The interval at which the event occurs becomes shorter).

After performing the prepurge as described above, the burner is ignited by opening the proportional valve with a predetermined amount of heat for ignition as shown in FIG. 4 (S28, S29). Subsequently, it is checked whether or not the general hot water supply is used (S30), and if it is used, it is next checked whether or not the abnormality occurrence possibility high mode is set (S31). If the result is not a high likelihood mode (that is, a low likelihood mode)
The flame current If is read (S32), and the lower limit Is of the normal range of the flame current determined according to the required combustion amount F at that time (for example, 250 μm when the combustion amount F is 16).
A) (S33, S34). As a result, if the flame current If exceeds the lower limit of the normal range Is, it is determined that the combustion state is normal. Then, the required combustion amount is determined based on the set temperature Ts, the incoming water temperature Tc, the incoming water amount Q, and the outlet water temperature Th. F is calculated (S35, S36), and the proportional valve opening and the fan speed are controlled based on the required combustion amount F (S37, S37).
38).

On the other hand, in step S34, the frame current If
Is lower than the normal range lower limit value Is, the possibility of occurrence of an abnormality is set, so that the abnormality occurrence high probability mode is set (S
40), and enters a combustion amount control routine to be described later (S4).
1) Then, subsequently, an abnormality determination routine to be described later is entered (S41).

Also, in the case where the possibility of occurrence of abnormality is high in step S31, the process immediately proceeds to step S40 to enter the combustion amount control routine, and subsequently to the abnormality determination routine (S41).

If the general hot water supply is not being used in step S30, it is next determined whether or not the reheating operation is to be performed alone (that is, the filling level Qf = 0) (S42).
If additional reheating is not performed alone, that is, if hot water is being filled, the routine immediately enters a combustion amount control routine (S41), and subsequently enters an abnormality determination routine (S41).

Here, it is determined that the flame current is normal when the flame current If exceeds the lower limit value Is of the normal range. However, in a certain burner configuration, if the flame current becomes abnormal, the flame current If becomes abnormal.
Is increased, the normal / abnormal state is determined for such a case by comparing the frame current If with the upper limit of the normal range.

On the other hand, in the case of the reheating alone operation, as shown in FIG. 5, first, the necessary combustion amount Ff for reheating is calculated based on the bath set temperature Tfs and the bath temperature Tf (S43), and then fixed. It is checked whether or not the combustion mode is being performed (S44). If the combustion mode is not being set, the fixed combustion mode is set.
The required combustion amount Ff calculated previously is set as the fixed combustion amount Fs (S46). Then, the proportional valve opening and the fan speed are controlled based on the fixed combustion amount Fs (S48), and then the abnormality determination routine is started (S49).

In the reheating alone operation, after once entering the fixed combustion mode, it is determined whether or not the difference between the fixed combustion amount Fs and the current required combustion amount Ff is within 2 (S5).
0) If the number is within 2 or less, the process proceeds to step S47 while maintaining the fixed combustion mode, and controls the proportional valve opening and the fan speed based on the fixed combustion amount Ffs. As described above, by fixing the combustion amount in the fixed combustion mode and eliminating the fluctuation, the abnormality determination can be accurately performed.

If the difference between the fixed combustion amount Fs and the current required combustion amount Ff exceeds No. 2 in step S50, the fixed combustion mode is canceled (S51), and the proportional combustion is performed based on the required combustion amount Ff. Control the valve exclusion and the fan speed (S5
2, S53). Thereby, combustion control can be performed so as to meet a user's request.

After the ignition, the above-described control of the proportional valve and the fan is repeated, and when a request to stop combustion is input (S54), that is, when the water flow rate Q becomes 0 and the bath temperature Tf becomes higher than the bath set temperature tTfs. Then, the fire is extinguished by closing the on-off valve of the burner (S55).

After the fire is extinguished, as shown in FIG. 6, first, the presence or absence of a combustion request is checked (S56), and if there is a combustion request, the flow returns to step S15 in FIG. 3 to restart the prepurge. If there is no request for combustion, it is next checked whether or not the mode is high in the possibility of occurrence of abnormality (S57). If the mode is not high (that is, the mode is low in the possibility of occurrence of abnormality), the fan speed of post-purge is checked. Relatively low rotation speed (for example,
2000 rpm) (S58), and post-purge is performed for a predetermined time (for example, 90 seconds) at the rotation speed (S58).
59, S63). During this post-purge, after the fan drive current If is stabilized (S60), the fan drive current If is compared with a reference value (S61). If the fan drive current If has not reached the reference value, there is a possibility of abnormality. Therefore, the abnormality occurrence possibility high mode is set (S62).

On the other hand, in the case of the mode with a high possibility of occurrence of abnormality in step S57, the rotation speed is sufficiently high for the post-purge fan rotation speed (for example, 4000 rpm, which is higher than the maximum rotation speed during combustion, for example, 3500 rotations). Is set (S64), and post-purge is performed at the high rotation speed for a predetermined time (for example, 90 seconds) (S65, S63). During the post-purge, after the fan drive current If is stabilized (S66), the fan drive current If is compared with a reference value (S66).
67) If the fan drive current If has not reached the reference value, it is determined to be abnormal and a warning is displayed (S68). As described above, in the abnormality occurrence possibility high mode, the abnormality determination is performed at a sufficiently high rotation speed, so that a highly accurate abnormality determination result can be obtained.

FIGS. 7 and 8 show the detailed flow of the combustion amount control routine in step S40 of FIG.

First, the required combustion amount F is calculated based on the set temperature Ts, the incoming water temperature Tc, the incoming water amount Q, and the outlet temperature Th (S70, S71), and the required combustion amount F exceeds a predetermined maximum combustion amount Fmax. Is checked (S7).
1). As a result, if it exceeds, the capacity over mode is set, and the proportional valve opening and the fan speed are controlled based on the maximum combustion amount Fmax (S73, S74, S97).

On the other hand, if the required combustion amount F does not exceed the maximum combustion amount Fmax, it is next checked whether or not the engine is in the fixed combustion mode (S75). If you are in fixed combustion mode,
If the difference between the fixed combustion amount Fs and the required combustion amount F is within two, the combustion is controlled based on the fixed combustion amount Fs while maintaining the fixed combustion mode (S76, S77, S97). If the difference becomes equal to or larger than 2, the fixed combustion mode is released and the combustion is controlled based on the required combustion amount F (S7).
6, S78, S86, S97).

If it is not in the fixed combustion mode in step 75, it is first checked whether the sample timer is operating (S79), and if not, it is next checked whether the steady state determination timer is operating (S80). If it is not in operation, after starting the steady-state determination timer (S81), it is determined whether or not the change in the required combustion amount between the previous time and this time is 1 or more.
Then, it is checked whether or not the integrated value of the change in the combustion amount after the start of the steady state determination timer is 2 or more (S82, S83). As a result, either the change in the combustion amount or the integrated value is 1
If the number is No. 2 or more, it is determined that combustion has not yet reached a steady state, and the steady state determination timer is reset (S8).
4) Then, the routine proceeds to step 86, where combustion control based on the required combustion amount F is performed.

On the other hand, if both the change in the combustion amount and the integrated value thereof fall below No. 1 and No. 2 in steps S82 and S83, it is then checked whether or not the steady state determination timer has reached 1 second or longer ( S85) If one second has not been reached, the routine proceeds to step 86, where combustion control based on the required combustion amount F is performed, while if it has been one second or longer, it is determined that combustion has reached a steady state. 87 is checked (S87), and if the sample timer is not running, it is started (S88), and step S89
Proceed to.

If it is determined in step S79 that the sample timer is in operation, the process immediately proceeds to step S89.
Proceed to.

In step S89, it is determined whether the change in the required combustion amount between the previous time and the present time is 1 or more, and whether or not the integrated value of the change in the combustion amount is 2 or more ( S
89, S90). As a result, when either the change in the combustion amount or the integrated value is No. 1 or No. 2 or more, it is determined that the combustion is not in the steady state, and the steady state determination timer is reset (S91), and the routine proceeds to step 86. Then, the combustion control based on the required combustion amount F is performed.

On the other hand, if the change in the combustion amount and the integrated value thereof are both lower than No. 1 and No. 2 in steps S89 and S90, it can be confirmed that the combustion is in a steady state. It is checked whether or not is more than 1 second (S92). As a result, if the sample timer has not yet reached one second or longer, the routine proceeds to step S86, where the combustion control based on the required combustion amount F is performed. The average value of the amounts is calculated and defined as the fixed combustion amount Fs (S
92). Here, the reason why the average value is set to the fixed combustion amount Fs is to obtain a tapping temperature as close as possible to the set temperature by using a fixed combustion amount as close as possible to the actual required combustion amount.

Next, it is checked whether or not the fixed combustion amount Fs exceeds a sufficiently high predetermined value (for example, No. 20, which is slightly lower than the maximum combustion amount, for example, No. 24) (S94). , If not, the fixed combustion amount Fs
Is ignored, the process proceeds to step S86, where control based on the required combustion amount F is performed. On the other hand, if it exceeds, the fixed combustion mode is set (S95), and combustion is controlled based on the fixed combustion amount F (S96, S97).

The reason why the fixed combustion mode is set only when the fixed combustion amount Fs is a sufficiently large combustion amount is that the subsequent abnormality judgment operation in the abnormality judgment mode is performed under a sufficiently large combustion amount. This is to ensure that the abnormality determination is performed accurately.

FIG. 9 is a flowchart showing the operation of step S41 in FIGS.
The detailed flow of the abnormality determination mode of S49 is shown.

First, it is checked whether or not the mode is the overcapacity mode or the fixed combustion mode (S98). If it is either mode, it is next checked whether or not the second abnormality determination timer is operating (S99). If it is not in operation, it is started (S100), and then the frame current If is read (S101). Next, if the stability determination timer has not been activated, it is started (S102, S103), and whether or not the change amount of the frame current If between the current time and the previous time exceeds a predetermined value (for example, 10 μA). And the integrated value of the change amount after the stability determination timer is activated is a predetermined value (for example, 2
0A) is checked (S104, S
105).

As a result, if either the amount of change in the frame current or the integrated value thereof exceeds the predetermined value, the combustion is not in a steady state, so the stability determination timer is reset (S111), and this routine ends. . On the other hand, if the frame current change amount and the integrated value are both less than the predetermined value, when the stability determination timer exceeds 1 second in this state (S106), the frame current If within one second is not exceeded. The average value Iave is calculated (S107), and this flame current average value Iave is compared with the normal range lower limit value Is of the flame current determined according to the required combustion amount F (S108,
S108). As a result, if the flame current average value Iave is less than the normal range lower limit value Is of the flame current, it is determined that the combustion is abnormal and a warning is displayed (S110).

If it is determined in step S99 that the second abnormality timer is in operation, it is checked whether the second abnormality timer has exceeded 2 seconds (S112). It is considered that an abnormal state in which the combustion state is not stable despite being performed (for example, a resonance combustion state or hunting of the drive circuit of the device) has occurred, and a warning display different from other warning displays is performed (S113). .

If neither the overcapacity mode nor the fixed combustion mode is selected in step S98, both the first abnormality determination timer and the stability determination timer are reset (S11).
4), end this routine.

While the preferred embodiment of the present invention has been described above, the present invention can be implemented in various modes other than this embodiment.

[0064]

As described above, according to the present invention,
It is possible to reduce the influence of the change in the combustion state due to the change in the combustion amount and improve the accuracy of the abnormality determination.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing the overall configuration of an embodiment of a water heater to which the present invention is applied.

FIG. 2 is an exemplary flowchart illustrating a use time and number integration routine of the embodiment;

FIG. 3 is a flowchart showing a part of a combustion sequence of the embodiment.

FIG. 4 is a flowchart showing a part of a combustion sequence of the embodiment.

FIG. 5 is a flowchart showing a part of the combustion sequence of the embodiment.

FIG. 6 is a flowchart showing a part of the combustion sequence of the embodiment.

FIG. 7 is a flowchart showing a combustion amount control routine of the embodiment.

FIG. 8 is a flowchart showing a combustion amount control routine of the embodiment.

FIG. 9 is a flowchart illustrating an abnormality determination routine according to the embodiment;

[Explanation of symbols]

 30 Control part Q Water flow Qf Filling amount Tc Inlet water temperature Th Outlet temperature Tf Bath temperature Tc Set outlet temperature Tfs Set bath temperature If Frame current Ifan Fan current

Continuation of the front page (72) Inventor Shigeo Yoshida 431-1 Uozakihama-cho, Higashinada-ku, Kobe-shi, Hyogo Prefecture Inside (72) Inventor Hiroshi Munemura 43-1 Uozakihama-cho, Higashinada-ku, Kobe-shi, Hyogo Nippon Yupro Stock In-company (56) References JP-A-5-196229 (JP, A) JP-A-7-127854 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F23N 5/24 110 F23N 5/18 101

Claims (7)

(57) [Claims] 1. An abnormal combustion determination device for a combustion device that controls an air supply amount and a fuel supply amount according to a required combustion amount, wherein a detection unit that detects a predetermined state amount when the combustion device burns, Eligibility judging means for judging whether the state quantity detected by the detecting means satisfies a predetermined eligibility condition indicating that the state quantity is eligible for use for abnormality determination, and the necessary combustion amount is the maximum combustion of the combustion equipment. When the amount exceeds the amount, the required amount of combustion is limited to the maximum amount of combustion, and the amount-of-combustion limiting means, and when the eligibility determining means determines that the eligibility condition is satisfied, based on the detected state quantity, Abnormality determination means for determining whether or not there is an abnormality; andwherein the abnormality determination means, when the combustion amount limiting means limits the required combustion amount to the maximum combustion amount, One is full An abnormal combustion determination device that is considered to have been performed. 2. An abnormal combustion determination device for a combustion device that controls an air supply amount and a fuel supply amount according to a required combustion amount, wherein: a detection unit that detects a predetermined state amount of the combustion device; Eligibility determining means for determining whether the state quantity detected by the above satisfies a predetermined eligibility condition indicating that the state quantity is eligible for use for abnormality determination, and the eligibility judging means satisfies the eligibility condition When it is determined, the abnormality determining means for determining whether there is an abnormality based on the detected state amount, the air supply amount or the fuel supply amount so as to achieve the intended use of the combustion equipment A first control unit for controlling the air supply amount or the fuel supply amount in a predetermined state in which the state quantity changes little; and a first control unit for controlling the first and second control units. Select one An abnormal combustion determination apparatus, wherein one of the eligibility conditions is that the second control means is selected. 3. The method according to claim 1, wherein the predetermined state quantity is a predetermined physical quantity indicating a driving state of the air supply fan in a pre-purge or a post-purge, and the first control unit controls the rotation of the fan in the pre-purge or the post-purge. The number and rotation time are controlled to a first rotation number and a first time suitable for the purpose of the pre-purge or post-purge, and the second control means controls the rotation number or the rotation number of the fan in the pre-purge or post-purge. The abnormal combustion determination device according to claim 2, wherein the rotation time is controlled to a second rotation speed higher than the first rotation speed or a second time longer than the first time. 4. The predetermined state quantity is a predetermined physical quantity indicating a combustion state, and the first control means controls the air supply amount and the fuel supply amount so as to burn at the required combustion amount. 3. The abnormal combustion determination device according to claim 2, wherein the second control means controls the air supply amount and the fuel supply amount so as to burn at a constant combustion amount. 5. The abnormality according to claim 4, wherein said selection means selects said second control means in place of said first control means when the control by said first control means enters a steady state. Combustion determination device. 6. The combustion apparatus for heating a fluid to be supplied to a user, wherein the selecting means is arranged such that the use mode of the combustion device is such that the fluid directly contacts the user. 3. The method according to claim 2, wherein the first use mode is selected in the first use mode, and the second control mode is selected in the second use mode. An abnormal combustion determination device according to the above. 7. The apparatus according to claim 2, wherein said selecting means determines whether a possibility of occurrence of an abnormality is high based on a predetermined condition, and selects said second control means when the possibility of occurrence of an abnormality is high.
An abnormal combustion determination device according to the above.