JPH0727414A - Control of combustion in hot-water heater in case of reuse - Google Patents

Abstract

PURPOSE:To enable controlling the amount of combustion with close care in details by a method wherein the amount of gas for the start-up of combustion for the resupply of hot water is corrected by an increase or decrease in a corrected amount of gas to compensate for a lag difference, which compensates the difference between the amount corresponding to a lag in start-up for the resupply of hot water and the amount corresponding to a lag in fall, and to compensate for variation in ignition performance. CONSTITUTION:A corrected amount of gas is obtained as a value compensating for a decrease or increase in the temperature of hot water from the difference between a drop D in hot-water temperature agreeing with falling characteristics GD and a rise U in hot-water temperature agreeing with rising characteristics GP. On the other hand, processing is done to obtain an amount of gas to compensate for a lag difference between a time lag LP in rise and a time lag LD in fall and an amount of gas to compensate for a lag in ignition (minimum throttling of gas in the case of an advance in ignition), which compensates for a lag or excess in rise of the temperature arising from variation in time of the ignition such as a lag in ignition or an advance in ignition. A finally corrected amount of gas is set by increasing or decreasing a corrected amount of gas by the amount of gas to compensate for a lag difference and by the amount of gas to compensate for variation in ignition performance. This method enables controlling the amount of combustion with close care in details.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion control method for hot water supply when hot water is re-opened, which stabilizes the hot water temperature when hot water is re-opened.

[0002]

2. Description of the Related Art FIG. 13 shows a general system configuration of a water heater. In the figure, a water supply pipe 3 is connected to the inlet side of the heat exchanger 2, and the water supply pipe 3 is provided with a water inflow thermistor 10 for detecting the water inflow temperature and a flow rate sensor 9 for detecting the water inflow amount. ing. The hot water supply pipe 4 is connected to the outlet side of the heat exchanger 2, and the hot water supply tap 1 is provided on the outlet side of the hot water supply pipe 4. Further, the hot water supply pipe 4 is provided with a water amount control valve 16 and a hot water discharge thermistor 11 for detecting the hot water temperature.

Below the heat exchanger 2, a burner 7 and a burner 7 are provided.
An igniter electrode 18 for igniting the engine, a frame rod electrode 19 for detecting ignition, and a combustion fan 5 for supplying / exhausting air are provided, and a gas nozzle 6 is provided at a gas inlet of the burner 7.
Are arranged opposite to each other, and a gas proportional valve 13 for controlling the gas supply amount by the valve opening amount in the gas pipe 8 leading to the gas nozzle 6.
And a gas solenoid valve 12 for opening and closing the pipeline.

This type of water heater is provided with a control device 14, and a remote controller 15 is connected to the control device 14. The remote controller 15 has buttons for setting the hot water temperature and a display part for the hot water set temperature. It is provided. The control device 14 controls the hot water supply operation of the water heater, and (a) of FIG. 13 and FIG.
As shown in (b), when the hot water tap 1 is opened, the flow rate sensor 9 detects the amount of water entering, and when the amount of water entering exceeds a certain level (minimum operating flow rate), a signal from the flow rate sensor 9 In response to this, the control device 14 rotates the combustion fan 5. Then, when the rotation of the combustion fan 5 enters a predetermined rotation region, the gas solenoid valve 12 and the gas proportional valve 13 are opened to supply the gas to the burner 7, and the ignition operation by the igniter electrode 18 is performed. When the flame rod electrode 19 detects the ignition of gas, the control device 14 performs feedforward control, changes the valve opening amount of the gas proportional valve 13, and performs stabilization control of the hot water temperature coming out of the heat exchanger 2.

In the feed-forward control after gas ignition, the gas amount gradually increases as shown in FIG. 12 (b) in accordance with the incoming water temperature and the incoming water amount, and combustion is performed. As shown in (c) of the figure, it takes time from the opening of the hot water tap 1 to the ignition without immediately rising, and further, after the gas is ignited, the heat due to the gas combustion is generated by the heat exchanger. from 2 until transferred to the water passing through the heat exchanger 2 to be time consuming, after all, from the past time delay t _p from the open water tap 1 hot water temperature is gradually increased, the hot water set temperature Reach and stabilize. After the stabilization of the hot water temperature, the combustion control is performed by combining feedforward and feedback. The change in the hot water outlet temperature shown in (c) of the figure is when the water heater is cold-started, that is, when the hot water supply device is installed and the hot water tap 1 is opened for the first time, or after the hot water supply combustion is stopped,
For example, the figure shows a case where the hot water is again discharged after a long time such as 10 minutes.

[0006]

On the other hand, when the hot water is used again immediately after the hot water supply is used, the temperature of the hot water remaining in the hot water supply is post-boiled as shown in Fig. 11 (a). Due to (a phenomenon in which the amount of heat stored in the heat exchanger 2 is transferred to the hot water remaining in the heat exchanger 2 and the hot water temperature rises), the hot water is higher than the hot water set temperature, but It is cooled by flowing water and descends. Further, the rise of the hot water temperature due to the combustion heating of the gas after the re-leaving hot water starts after the time t _p as described above.

At this time, if the cooling rate of the hot water temperature is higher than that of the hot water temperature due to combustion heating,
In order to raise the water entering the water heater to the hot water set temperature, the gas-fired power cannot catch up, and at the time of re-leaving hot water, the hot water that is higher than the hot water set temperature initially comes out, but after that, the undershoot water that is considerably lower than the hot water set temperature There is a fluctuation in the hot water temperature, and if the cooling rate of the hot water temperature is faster than the rising speed of the hot water temperature, the overshoot hot water with a hot water temperature higher than the set temperature will continue to come out. There is a problem,
In either case, the user of hot water was uncomfortable.

The present invention has been made in order to solve the above-mentioned conventional problems, and an object of the present invention is to make it possible to comfortably use hot water by preventing undershooting and overshooting of hot water at the time of re-hot water. It is to provide a method for controlling combustion when the hot water heater is re-opened.

[0009]

In order to achieve the above object, the present invention is constructed as follows. That is, the combustion control method at the time of hot water re-emergence of the water heater of the present invention, the rising characteristics of the hot water temperature by cold start of the water heater,
The fall characteristic of the residual hot water temperature in the water heater after the combustion is stopped after the set hot water temperature, and the rising delay amount of the hot water rising characteristic from the start of re-leaving hot water to the start of rising hot water temperature,
The hot water temperature is higher than the set temperature After the boiling point, the hot water temperature falls until the hot water set temperature is reached. Correspondingly determined in advance, when the hot water is re-opened after combustion stop of the water heater, there is a decrease in the hot water temperature obtained from the falling characteristic of the hot water temperature and a rise in the hot water temperature obtained from the rising characteristic of the hot water temperature. A correction gas amount that makes the subtracted temperature difference zero by comparison from the point of re-melting hot water is obtained, while a delay difference for compensating hot water temperature fluctuations corresponding to the delay difference between the fall delay amount and the rise delay amount at the time of re-melting hot water. Calculate the gas compensation amount, detect the ignition delay, and if ignition delay occurs, calculate the ignition delay gas compensation amount that compensates for the insufficient rise in hot water temperature due to the ignition delay amount. Hot water Is the delay gas compensation amount when there is a difference between the hot water rise delay amount and the hot water fall delay amount when the startup gas amount is increased or decreased by the correction gas amount, and the ignition delay when there is an ignition delay. Combustion is performed by compensating for each gas compensation amount, and the presence or absence of ignition progress is detected, and at the time of re-leaving hot water, the startup gas amount is increased / decreased and corrected by the correction gas amount. If there is a difference between the rising delay amount and the hot water falling delay amount, the delay difference gas compensation amount is compensated, and if there is ignition advance, the ignition gas progress is narrowed down to the minimum to maintain the flame from the time of ignition. It is also a characteristic configuration of the present invention to start up and burn after waiting for a minute.

[0010]

[Operation] Utilizing the rising characteristic of the hot water temperature and the falling characteristic of the residual hot water temperature in the water heater after the preset hot water temperature corresponding to each condition of the incoming water temperature, the amount of incoming water and the preset hot water temperature The amount of correction gas to be increased or decreased to eliminate the difference in temperature difference between the decrease in the hot water temperature due to the falling characteristics of the hot water temperature and the increase in the hot water temperature due to the rising characteristics of the hot water when re-leaving hot water is calculated. Is increased / decreased to the amount of startup gas at the time of re-hot water, and when there is a difference between the rising delay amount of the hot water rising characteristic and the falling delay amount of the hot water falling characteristic, the delay difference gas compensation amount is increased / decreased. ,
Furthermore, when there is a delay in ignition, the ignition delay gas compensation amount is compensated, and when there is ignition progress, the startup timing of the startup gas amount is delayed by narrowing the gas amount by the ignition advance amount, so The undershoot and overshoot of can be kept small, and the hot water can be used comfortably with the hot water set temperature maintained.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. Note that the water heater system in the present embodiment is the same as that shown in FIG. 13, and the same names as those in the conventional example are designated by the same reference numerals, and duplicate description thereof will be omitted.

In this embodiment, the residual hot water temperature in the hot water supply apparatus at the time of re-leaving hot water is lowered by the water flow in the hot water supply apparatus G _D, and the hot water temperature rises by the gas combustion. By paying attention to the fact that both the characteristics G _P and the hot spring effect on the hot water discharge temperature, the gas combustion amount at the time of hot water discharge is controlled so that undershoot and overshoot do not occur at the time of hot water discharge again.

As shown in FIGS. 4 (a) and 5 (a), the falling characteristic G _D of the residual hot water temperature in the water heater has a combustion in which the hot water tap 1 is closed and the flow sensor 9 is turned off. It shows the temperature change at the hot-water tap outlet when the hot-water tap 1 is opened again without igniting after stopping, and this temperature is until the hot water temperature falls to the hot-water set temperature after post-boiling. After the delay time L _D as the trailing delay amount has elapsed, the hot water temperature drops below the hot water supply set temperature. Further, the rising characteristic G _P (G _P1 , G _P2 ) of the hot water temperature has a delay time L _P as a rising delay amount after the hot water tap 1 is opened and the flow sensor 9 is turned on until the temperature rise is started. Hot water temperature rises after passing. A curve _C which is a combination of a curve representing the falling characteristic G _D of the hot water having such a fall delay time L _D and a curve representing the rising characteristics G _P1 and G _P2 of the hot water having the rise delay time L _{P 1} and C ₂ are
It is a curve showing the change in hot water temperature after re-outflow.

The characteristic of FIG. 4 is the rising characteristic G _{P1 of the} hot water temperature.
This is the case where the falling speed of the hot water temperature G _D is faster than the rising speed of
On the contrary, the rising speed of the hot water temperature rising characteristic G _P2 is higher than the falling speed of the hot water temperature falling characteristic G _D. In addition, in FIG. 4B and FIG. 5B, the curve GG _D is the rising characteristic G _P (G
_In order to make it easier to compare _P1 and G _P2 ) with the fall characteristic G _D , the fall characteristic G _D is reversed and the starting point position is drawn so as to coincide with the starting point position of the rising characteristic G _P.

Generally, when the previous hot water supply combustion before re-leaving hot water was used with a small amount of heat, the heat exchanger 2 is stopped when the combustion is stopped.
When the re-leaving hot-air combustion in which the heat capacity held inside is small and the next-largest amount of hot-water coming out is performed in this state, the speed of the falling characteristic becomes higher than that of the rising characteristic. Similarly, when the previous hot water supply combustion before re-hot water was performed at a low temperature setting, the set temperature was changed at the time of the next re-hot water and re-hot water was performed at a high temperature setting, or the heat exchanger because, for example 2 of the can body is small, if such rate of falling characteristics than the rise characteristic has a fast intrinsic characteristics, the hot water temperature rising characteristic G _P than the rise rate of the hot water temperature The falling speed of the falling characteristic G _D becomes higher, and the undershoot water as shown by the curve C ₁ in FIG. 4 comes out.

On the other hand, after a large amount of heat is used in the combustion operation before the hot spring is reheated, when the hot water is discharged again next time, a small amount of heat is used with a small flow rate of hot water, or a high temperature is set before the hot water is reheated. After it has been used for the next time, it is necessary to use a characteristic that the rising speed is faster than the falling speed when it is used at a low temperature setting or as a unique temperature characteristic of the heat exchanger 2. When it has, the rising characteristic G of the hot water temperature is faster than the falling characteristic G _D of the hot water temperature.
The rising speed of _P becomes higher, and when the hot water is again tapped, it becomes the above-mentioned curve of C ₂ , and the hot water of overshoot comes out.

As is well known, the hot water fall characteristic G _D , its fall delay time L _D , and the hot water rise characteristic G
_P and its rising delay time L _P change depending on various conditions such as the water temperature at the time of re-hot water, the amount of water input, and the hot water supply set temperature. For example, as shown in FIGS. 10 (a) and 10 (b), when the incoming water temperature is T ₁ and the hot water supply set temperature is T _S , the incoming water amount (I ₁ >)
I ₂ > I ₃ ) changes, the falling characteristics G _D1 , G _D2 , G _D3 of the hot water temperature and the falling delay times L _D1 , L _D2 , L
_D3 changes. The greater the amount of water entering, the faster the heat dissipation rate of the heat exchanger 2, so that the residual hot water temperature in the water heater has a falling characteristic of the hot water temperature, and the falling delay time becomes shorter. Further, although not shown in the figure, it takes time to raise the hot water temperature as the amount of incoming water increases, so it has a rising characteristic of the hot water temperature that the hot water temperature rises slowly. Since the detection can be performed early and the ignition operation is accelerated, the rise delay time is shortened.

Further, after the last combustion stop, that is, after the hot water tap 1 is closed and the flow rate sensor 9 is turned off,
The fall delay time L _D changes depending on the hot-water tap waiting time until the hot-water tap 1 is opened and the flow sensor 9 is turned on until the hot-water tapping is restarted.

[0019] In this embodiment, incoming water temperature, incoming water, hot water set temperature falling characteristic G _D Yu corresponding to various conditions of the re-pouring wait time temperature, fall delay time L _D, the hot water rising characteristics of temperature G _{It is characterized in that P 1} and rise delay time L _P are obtained in advance by experiments or theoretical calculations and are stored as relational data.

In this embodiment, the relational data given in advance corresponding to the water temperature, the amount of water input, and the hot water supply set temperature at the time of re-hot water are used to make the water flow at the time of re-hot water and other conditions The falling characteristics G _D of the hot water temperature, the falling delay time L _D , the rising characteristics G _P of the hot water temperature, and the rising delay time L _P are calculated and used to prevent undershoot and overshoot in the hot water temperature. A correction gas amount as shown in (a) of FIG. 6 and (a) of FIG. 7 for increasing / decreasing the gas amount when tapping hot water is obtained.

[0021] That is, if the speed of the falling characteristic G _D than the rise characteristic G _P1 is large, water temperature falling characteristic G _D after falling delay time L _D elapses as shown in FIG. 4 (a) a hot water temperature drop D by, the gas corresponding to the residual drop D-U ₁ as the difference between the rise U ₁ of hot water temperature by rising characteristic G _P1 of the hot water temperature after the passage of a rising delay time L _P combustion The amount is calculated as a correction gas amount for an increase as shown in FIG. 6 (a), and this amount is added to the startup gas amount at the time of re-hot water to compensate the residual hot water temperature drop D-U _1. The undershoot of the hot water temperature at the time of re-hot water is kept small, and the hot water temperature is stabilized.

Further, when the speed of the rising characteristic G _P2 is higher than that of the falling characteristic G _{D, the} hot water temperature increasing amount U ₂ is larger than the hot water temperature decreasing amount D as shown in FIG. As shown in (a) of Fig. 7, the residual temperature rise amount U ₂ −
A correction gas amount corresponding to the decrease in gas corresponding to D is calculated and subtracted from the startup gas amount at the time of re-hot water to compensate for the residual temperature increase U ₂ -D of the hot water to compensate for the re-hot water. It suppresses the overshoot of the hot water temperature and stabilizes the hot water temperature.

The rising delay time L _P , which is given in advance as the relational data, is set such that after the hot water tap 1 is opened and the flow rate sensor 9 is turned on, the gas is ignited by combustion after a fixed reference ignition time t _f0. It is given on the assumption that it will be given.

FIG. 1 shows a block diagram of a correction gas amount control unit 25 for carrying out a combustion control method at the time of re-hot water discharge of the water heater according to the present invention. The correction gas amount control unit 25 is formed in the control device 14, and a water entry detection unit 26, an ignition detection unit 27, a correction gas amount setting unit 28, a data storage unit 29, and a gas proportional valve drive unit 30. , And a plurality of timers 31 and a memory 32.

When the hot water tap 1 is opened,
When the signal from the flow rate sensor 9 is applied, the timer 31 is operated for a predetermined time, the signal from the flow rate sensor 9 within the timer time is measured, and this is converted into the flow rate and detected as the amount of incoming water. Further, the incoming water thermistor 10 detects the incoming water temperature. Further, the water inflow detection unit 26 waits for re-releasing hot water after combustion is stopped, that is, when the hot water tap 1 is closed and the flow rate sensor 9 is turned off until the hot water tap 2 is opened and the flow rate sensor 9 is turned on again. Is calculated by the operation of the timer 31. The amount of entering water, the entering water temperature, and the hot water re-waiting time detected by the entering water detector 26 are temporarily stored in the memory 32, respectively.

In the ignition detection section 27, the timer 31 operates the ignition time t _f from the start of re-hot water discharge when the hot water tap 1 is opened and the flow sensor 9 emits an ON signal to the time when the ignition of the gas by the frame rod electrode 19 is confirmed. And the ignition time t _f is temporarily stored in the memory 32. On the other hand, the ignition detection time than calculating the t _f and the reference ignition time t _f0 calculated the ignition delay amount (t _f -t _f0) and the ignition advance amount (t _f0 -t _f), stores this in the memory 32 To do.

As described above, the water 32 is detected in the memory 32.
Data such as the incoming water temperature, the incoming water amount, the re-hot water waiting time, the ignition time t _f added from the ignition detection unit 27, the ignition delay advance time, and the like are stored. Further, the reference ignition time t given in advance is stored. _The hot water supply set temperature and the like set by _f0 and the remote controller 15 are stored. It is also used as a temporary storage location for the graph data and the like obtained by the correction gas amount setting unit 28.

The data storage section 29 shows the rising characteristics G _P and the falling characteristics G _D of the hot water temperature for each of the conditions of the incoming water temperature, the incoming water amount, the hot water supply set temperature, and the re-hot water waiting time. Graph data and rising delay time L _P ,
The fall delay time L _D is obtained in advance by experiments or the like and stored as related data.

As shown in FIG. 2, the correction gas amount setting unit 28 has an ignition fluctuation gas correction unit 34, a graph creating unit 35, and a correction gas amount calculation unit 36.

When the ignition delay occurs, the ignition fluctuating gas correction unit 34 obtains an ignition delay gas compensation amount for compensating the shortage of the rise in hot water temperature according to the ignition delay time, and when ignition advance occurs, after ignition occurs. The minimum throttle gas amount that can maintain the flame for the ignition progress is calculated, and these calculated values are added to the graph creating unit 35.

The graph creating unit 35 confirms the presence or absence of ignition delay or ignition advance. When there is no ignition delay or advance, the rising temperature characteristic G _P and the falling characteristic G _{D of} the hot water temperature under the condition of re-leaving hot water, Rise delay time L _P ,
The fall delay time L _D is read from the relational data stored in the data storage unit 29 and, for example, (b) in FIG.
And a graph as shown in FIG. 7B is created. That is, a curve of the hot water temperature rising characteristics G _P1 and G _P2 is drawn starting from the end point of the rising delay time L _P , and a curve of the hot water falling characteristic G _D starts from the end point of the falling delay time L _D. Draw. In this embodiment, in the state where there is no ignition delay or ignition advance, the rising delay time L _P and the falling delay time L _D are processed by software so as to be the same (L _P = L _D ), and the correction gas amount is set. Processing such as calculation is performed.

An arithmetic circuit is formed in the correction gas amount calculation unit 36, and based on the graph created by the graph creation unit 35,
Calculate the correction gas amount. As shown in FIG. 6, when the falling speed of the falling characteristic G _D is higher than the rising characteristic G _P , the subtraction calculation of the rising amount U ₁ of the hot water temperature from the falling amount D of the hot water temperature is performed in FIG. Is required as shown in.
The curve GG _{D in} the figure is the same as in FIG. 4 and FIG.
Similar to the one shown in FIG. 4, the falling characteristic of the hot water temperature is reversed to the rising characteristic G _P1 of the hot water temperature so that the starting point is the same. This temperature difference portion of D-U ₁ causes the undershoot of the hot water temperature characteristic C ₁ shown in (b) of the figure, and in the present embodiment, the temperature difference D-U ₁ is increased to eliminate it. Calculate the correction gas amount for minutes. Note that G _P1 ′ in FIG.
Is the rising characteristic of the hot water temperature when the correction gas amount is increased and corrected.

Further, in the case shown in FIG. 7 is greater rise velocity of Falling Rising than the rate characteristics G _P falling characteristics G _D of hot water temperature, the increase in water temperature correction gas amount calculating section 36 min U ₂ The drop D of the hot water temperature is subtracted from the calculated value, and the correction gas amount for reducing the excess temperature difference is calculated as shown in FIG. It should be noted that G _P2 ′ in FIG. 7 is a falling characteristic of the hot water temperature when the correction gas amount is reduced and corrected.

On the other hand, when there is ignition delay or ignition advance, the graph creating section 35 creates a graph in consideration of this ignition delay or advance. FIG. 8 and FIG. 9 show an example of this graph creation. FIG. 8 shows a case where the falling speed of the falling characteristic G _D of the hot water temperature is higher than the rising speed of the rising characteristic of the hot water temperature and the ignition delay Δt occurs. In this case, the rising delay time of the rising characteristic G _P1 ′ of the hot water temperature after the correction gas amount is corrected is the rising delay time L _P (L _P = L _P = L _P when there is no ignition delay).
It becomes L _{P1 by} extending approximately Δt ₁ from L _D ).

In this case, even if the correction gas amount obtained when there is no ignition delay is added, it corresponds to the ignition delay amount of the rising characteristic G _P1 ′ of the hot water temperature as shown in FIG. 8 (a). A shortage DD _{1 of} rising the hot water temperature occurs, and an undershoot of the hot water temperature occurs due to the shortage DD ₁ .

In order to prevent this, the correction gas amount calculation unit
36 calculates the ignition delay gas compensation amount that compensates for the shortage of the rise in hot water temperature corresponding to this ignition delay. G _P1 ″ in FIG. 8 is the rising characteristic of the hot water temperature when the ignition delay gas compensation amount is added.

On the other hand, as shown in FIG.
When the ignition advance of Δt occurs, the rising delay time of the rising characteristic G _P1 ′ of the hot water temperature after the correction gas amount increase correction is shorter than L _P when there is no ignition advance L _{P2 by} Δt.
Becomes If this ignition advance occurs, the amount of ignition advance DD
Excess of gas supply corresponding to ₂ occurs, and due to this, an overshoot of the hot water temperature occurs.

In the present embodiment, in order to eliminate the excessive amount of gas supply due to the progress of ignition, as shown in FIG. 9B, after confirming the ignition, the lower limit value of the flame does not extinguish. After the gas amount is throttled and the gas amount throttled state is held by Δt, the corrected gas amount is corrected and the corrected gas amount is started. G
_P1 ″ indicates the rising characteristic of the hot water temperature at this time.

The gas proportional component drive unit 30 is based on the correction gas amount calculated in the correction gas amount setting unit 28 calculated in each of the above cases, the delay difference gas compensation amount of the rising and falling characteristics, and the gas compensation value of the ignition variation. , The opening amount of the gas proportional valve 13 is controlled. For example, in the case shown in FIG. 6, the startup gas amount is controlled by adding the correction gas amount to the startup gas amount after ignition. As a result, the rising characteristics of the hot water temperature before correction G _P1
Becomes a reversal fall characteristic GG _D and G _P1 ′, and as shown in (b) of the figure, the outlet heated water temperature characteristic after post-boiling is a characteristic of C ₀₁ in which the heated water temperature is stable at the set temperature.

Further, in the case of FIG. 7, the correction gas amount from the rising gas amount after the ignition is reduced correction, the rising characteristics of the uncorrected hot water temperature G _P2 is inverted falling characteristic GG equal to _D G _P2 ' Therefore, as shown in (b) of the same figure, the tapping temperature characteristic after the post-boiling is obtained as a stable characteristic C ₀₂ which is almost equal to the set temperature.

Further, in the case of FIG. 8, the correction gas amount for the falling speed of the falling characteristic of the hot water temperature is larger than the rising speed of the rising characteristic and the ignition delay gas compensation amount for compensating the ignition delay are set. The hot water temperature is increased and corrected to obtain a stable characteristic C ₀₁ ″ that is substantially equal to the set temperature.

Further, in the case shown in FIG. 9, ignition progress Δ
delay the timing of starting the gas amount by t minutes, and
After ignition, the time amount of gas Δt is narrowed down to the lower limit value and stands by, so that the rising characteristic of the hot water temperature becomes a stable characteristic of G ₀₂ ″.

Next, the specific operation of this embodiment will be briefly described with reference to the flow chart shown in FIG. After turning on the power of the water heater, make sure that the hot water tap 1 is opened and the flow rate sensor 9 is turned on. As a cold start, the gas is ignited in steps 101 and 102 to check the incoming water temperature and incoming water amount. The control of the gas amount and the combustion control are performed by the normal feedback control according to the above.

Next, in step 103, it is judged whether or not the hot water tap 1 is closed, that is, whether or not the signal of the flow rate sensor 9 is off. If not, the process returns to step 101 to perform the normal gas combustion operation. continue. When the flow rate sensor 9 is turned off, the gas combustion operation is stopped in step 104, and the timer 31 for measuring the re-leaving hot water waiting time is operated.

Next, at step 105, when the hot water supply tap 1 is opened and the flow rate sensor 9 is turned on and re-hot water is confirmed,
The timer 31 for measuring the re-emergence waiting time measures the re-emergence waiting time. In Step 106, the waiting time for re-extra hot spring is 10
If it is within 10 minutes, if it is over 10 minutes, the process returns to step 101 and the combustion at the cold start is performed. If the waiting time for re-outflow is within 10 minutes, step 107
The operation for correcting the amount of gas at the time of tapping again is performed as shown in ~ 116.

In step 107, the ignition detection unit 27 determines whether or not the gas is ignited by the frame rod electrode 19, and if not, the process waits until the gas is ignited, and the ignition of the gas is confirmed. Then, in step 108, the ignition time t _f is measured by the timer 31 for measuring the ignition time.

Next, at step 109, conditions for re-outflowing hot water such as a water temperature and a water amount are detected. In step 110, the correction gas amount setting unit 28 pre-stores the hot water temperature rising characteristic G _P , the rising delay time L _P , the hot water falling characteristic G _D , and the falling delay time stored in the data storage unit 29 in advance. Read L _D. Further, the ignition variation time of ignition delay or ignition advance is obtained from the values of the ignition time t _f and the reference ignition time t _f0 .

In step 111, the amount of correction gas for the decrease in hot water temperature (or the increase in hot water temperature) is calculated by the difference between the decrease _{D in the} hot water temperature due to the falling characteristic G _D and the increase U in the hot water temperature due to the rising characteristic G _P. And the delay difference gas compensation amount between the rising delay time L _P and the falling delay time L _D, and the temperature increase delay DD ₁ (or the temperature increase excess DD ₂ ) due to the ignition variation time of ignition delay or ignition advance. Ignition delay gas compensation amount (minimum gas throttle amount in the case of ignition advance) is calculated. The final correction gas amount is set by adding or subtracting the delay difference gas compensation amount and the gas compensation amount due to the ignition fluctuation to the correction gas amount. In step 112, the amount of gas at the time of tapping again is compensated by the corrected amount of gas, the opening amount of the gas proportional valve 13 is controlled so as to be supplied to the burner 7, and the burner 7 burns gas.

Next, at step 113, it is judged whether or not the hot water outlet temperature is the hot water supply set temperature, and if not, the process waits until the hot water temperature stabilizes at the set temperature. If the hot water outlet temperature has reached the hot water supply set temperature and is almost stable in step 113, the correction gas amount control operation is terminated in step 114, and normal feed forward and feedback are combined to set the hot water outlet temperature to the hot water supply set temperature in step 115. The control moves to combustion operation.

The gas combustion operation by the combined feedforward and feedback control is continued until the hot water tap 1 is closed and the flow rate sensor 9 is turned off in step 116.
When the flow rate sensor 9 is turned off, the process returns to step 104 to stop the combustion, and waits for the next hot water discharge again.

According to this embodiment, the rising characteristic G _P , the falling characteristic G _D , the rising delay time L _P , and the falling delay time L _{D of} the hot water according to the detected data such as the incoming water temperature and the amount of incoming water are successively calculated. obtained by using the relationship data, drop D-U ₁ of hot water (or increment U ₂ -D) and the delay time L _D,
The amount of correction (compensation) gas that compensates for the difference in L _P deviation and ignition fluctuation is added (or reduced) to the start-up gas amount at the time of re-hot water to burn, so that the temperature of the hot water at the time of hot-water re-opening is under The shoot (or overshoot) can be kept small.

The present invention is not limited to the above-mentioned embodiment, and various embodiments can be adopted. For example, in the above embodiment, the cold start time is set when the re-hot water waiting time is 10 minutes or more, but the number is not limited to this value, and may be changed depending on the size of the water heater or other conditions. .

In the above embodiment, the amount of water input, the temperature of water input,
Conditions such as hot water supply set temperature are set, and the data storage unit 29 uses the rising characteristics G _P of rising temperature, rising delay time L _P , falling characteristics of hot water temperature G _D , and falling delay time L _D of each condition as related data. However, a more accurate correction gas amount can be obtained by considering the conditions such as the ambient temperature and the previous combustion amount immediately before the stop of the hot water supply combustion in addition to the above conditions.

Further, in the above embodiment, the rising characteristic G _P and the falling characteristic G _D of the hot water temperature are given in units of time, and the rising delay amount and the falling delay amount of each of these characteristics G _P and G _D are given. In addition, the supply of the amount of start-up gas and the amount of correction gas at the time of re-hot water, the ignition point and the delay or advance of ignition were also given time as a scale unit to control the stabilization of the hot water temperature. Instead, the amount of incoming water detected by the flow rate sensor 9 may be given as a scale unit to control the stabilization of the hot water temperature. The flow path cross-sectional area of the flow rate sensor installation part of the water heater is obtained as a known value, and if the integrated flow rate of the incoming water is divided by the flow velocity, it becomes the value of time, and therefore the time and the incoming flow rate are closely related to each other. Therefore, the time scale unit can be replaced with the incoming water amount scale unit, and the operation of the present embodiment can be performed using the incoming water amount scale unit.
As described above, the present invention is applied to a combustion control method in which the amount of incoming water is scaled in addition to the time scaled.

[0055]

EFFECT OF THE INVENTION The present invention uses the relational data of the rising characteristic of the hot water temperature and the falling characteristic of the hot water temperature corresponding to each condition such as the incoming water temperature, the incoming water amount, the hot water supply set temperature, etc. Calculate the correction gas amount that makes the temperature difference between the hot water falling and rising characteristics zero under the conditions, and add the correction gas amount to the delay to compensate for the difference between the rising delay amount and the falling delay amount at the time of re-leaving hot water. The difference gas compensation amount and the amount of gas that compensates for ignition fluctuations are increased and decreased to the startup gas amount when re-leasing hot water and burned, enabling precise control of the combustion amount and undershooting the hot water temperature when hot water is re-leaving. And overshoot can be further reduced, and hot water with a stable hot water temperature can be discharged.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment for carrying out a combustion control method when hot water is re-applied from a water heater according to the present invention.

FIG. 2 is a block diagram showing a detailed configuration of a correction gas amount setting unit.

FIG. 3 is a flowchart showing a specific operation of the embodiment.

FIG. 4 is a characteristic explanatory diagram when the falling speed of the hot water temperature is higher than the rising speed of the hot water temperature.

FIG. 5 is a characteristic explanatory diagram when the rising speed of the hot water temperature is higher than the falling speed of the hot water temperature.

FIG. 6 is a characteristic explanatory diagram showing a relationship before and after correction when the falling speed of the hot water temperature is higher than the rising speed of the hot water temperature.

FIG. 7 is a characteristic explanatory diagram showing a relationship before and after correction when the rising speed of the hot water temperature is higher than the falling speed of the hot water temperature.

FIG. 8 is a characteristic explanatory diagram showing a relationship before and after correction when a falling speed of the hot water temperature is higher than a rising speed of the hot water temperature and an ignition delay occurs.

FIG. 9 is a characteristic explanatory diagram showing a relationship before and after correction when the falling speed of the hot water temperature is higher than the rising speed of the hot water temperature and when the ignition advance occurs.

FIG. 10 is a graph showing changes in falling characteristics of hot water temperature due to changes in the amount of water entering.

[Fig. 11] Fig. 11 is a graph showing changes in hot water discharge temperature during conventional re-hot water discharge.

[Fig. 12] Fig. 12 is a graph showing a combustion operation at a cold start of the water heater.

FIG. 13 is a system configuration diagram of a water heater.

[Explanation of symbols]

D Hot water temperature drop amount U Hot water temperature rise amount G _D Hot water temperature fall characteristic G _P Hot water temperature rise characteristic L _D Fall time delay time L _P Rise time delay time

Claims (2)

[Claims] 1. A rising characteristic of hot water temperature due to cold start of the water heater, a falling characteristic of residual hot water temperature in the water heater after hot water supply after a combustion stop, and a rising temperature from the start of re-hot water The rise delay amount of the hot water temperature rising characteristic until the start and the fall delay amount of the hot water temperature falling characteristic until the fall start of the hot water temperature falling characteristic until it reaches the hot water supply set temperature after passing through the boiling point higher than the set temperature At least the water temperature, the amount of water input, and the hot water set temperature are obtained in advance, and the amount of decrease in the hot water temperature obtained from the falling characteristics of the hot water temperature and the hot water temperature at the time of re-leaving hot water after the hot water heater has stopped burning The amount of correction gas that makes the subtraction temperature difference compared with the rising time of the hot water obtained from the rising characteristics of the hot water from the starting point is obtained, while the falling delay amount and the rising time are The delay difference gas compensation amount for compensating the hot water temperature fluctuation corresponding to the delay difference of the delay amount is calculated, and the presence or absence of ignition delay is further detected.When the ignition delay occurs, the hot water caused by the ignition delay amount is detected. There is a difference between the hot water rise delay amount and the hot water fall delay amount when the ignition delay gas compensation amount is calculated to compensate for the insufficient rise in temperature, and the startup gas amount is increased or decreased with the correction gas amount when re-leaving hot water. A combustion control method at the time of hot water re-spouting, in which the combustion is performed by compensating the delay differential gas compensation amount when the ignition delay gas compensation amount is present and the ignition delay gas compensation amount when the ignition delay is present. 2. When there is a difference between the hot water rising delay amount and the hot water falling delay amount when the ignition gas progress is detected and the hot gas amount is increased / decreased and corrected by the correction gas amount at the time of re-hot water, 2. The water heater according to claim 1, wherein the delay differential gas compensation amount is compensated, and when there is ignition advance, the amount of gas to be started is narrowed down from the time of ignition to a minimum to maintain the flame, and the start-up combustion is performed after waiting for the amount of ignition advance. Combustion control method at the time of tapping again.