JP3091781B2 - Hot water temperature control device for water heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water heater such as a gas instantaneous water heater, and more particularly to a hot water temperature control device suitable for controlling the temperature of hot water from the hot water heater.

[0002]

2. Description of the Related Art Conventionally, in this type of hot water temperature control apparatus, for example, hot water from a gas instantaneous water heater and water from a tap water are mixed by a mixing valve according to the degree of mixing, and hot water at a set temperature is discharged. There is something.

[0003]

By the way, in such a configuration, the degree of mixing of the mixing valve is controlled so as to reduce the temperature deviation between the set temperature and the temperature of hot water from the mixing valve. This control, for example,
In the case of proportional differential control, that is, PD control, the proportional gain and the differential gain usually take constant values, respectively, so that good tapping temperature characteristics can be obtained for all of a wide variety of operating conditions of the gas instantaneous water heater. PD control is difficult.

For example, when the temperature deviation is large or the amount of hot water is large, the proportional gain or the differential gain is increased. On the other hand, when the temperature deviation is small or the amount of hot water is small,
If you do not reduce the proportional gain and derivative gain,
Good hot water temperature characteristics cannot be obtained. In particular, in PD control,
As the amount of hot water is smaller, hunting of the hot water temperature is more likely to occur,
If the proportional gain or the differential gain is selected so as to prevent hunting of the tapping temperature for all of the various use conditions of the instantaneous gas water heater, the control response deteriorates.

[0005] In view of the above, the present invention has been made to address such a problem, and in a hot water temperature control device for a water heater, regardless of a variety of changes in the operating conditions of the water heater, the outlet water temperature characteristic is always responsive. It is intended to perform hot water temperature control so as to maintain good condition.

[0006]

In order to solve the above-mentioned problems, a structural characteristic of the present invention is that a heat from a water supply source is heated according to heat energy from a heat energy supply source to generate hot water. An exchanging means, and a mixing means for mixing the hot water from the heat exchanging means and the water from the water supply source according to the degree of mixing, wherein the hot water from the mixing means discharges hot water. A tapping temperature detecting means for detecting a tapping temperature of hot water from the means, a tapping quantity detecting means for detecting a tapping quantity from the heat exchange means or the mixing means ,
Temperature difference which is the difference between the set temperature of hot water and the detected hot water temperature, and
Control means for controlling the degree of mixing of the mixing means so that the temperature of the hot water reaches the set temperature promptly in response to at least one change in the detected hot water amount. .

[0007]

According to the present invention, the control means makes it possible to control the set temperature of the hot water to be discharged.
Since the degree of mixing of the mixing means is controlled to quickly bring the tapping temperature of the hot water to the set temperature in accordance with at least one of the temperature deviation which is the difference between the detected tapping temperatures and the detected tapping amount , the use of the water heater is not required. Regardless of how the condition changes, the difference between the set temperature of the hot water to be discharged due to this change and the detected hot water temperature
The degree of mixing of the mixing means is controlled so as to quickly reach the set temperature of the hot water in accordance with at least one of the temperature deviation and the change in the detected hot water amount . Therefore, no matter how the use condition of the water heater changes, the control toward the set temperature of the hot water temperature is quickly performed with good responsiveness. It also controls the degree of mixing of the mixed-means as described above
Because of the is, be varied how use conditions of water heater, that no generated hunting tapping temperature.

In the present invention, the control means may include:
Calculating means for performing a proportional operation or a proportional differential operation on the degree of mixing of the mixing means so that the hot water temperature of the hot water reaches a set temperature in accordance with a change in the detected hot water temperature;
The degree of mixing, the detected tapping weight and has a correction means for correcting the fuzzy inference in accordance with the change in at least one of the detection tapping temperature, control the degree of mixing of the mixing means towards the correct degree of mixing of the correction means In such a case, a combination of the calculation result of the calculation means and the correction result of the correction means, that is, the proportional calculation or the proportional differentiation operation and the correction by the fuzzy inference thereof are used to perform the proportional calculation or the proportional differentiation operation. While effectively utilizing the advantages of the above, the disadvantages thereof can be compensated for by correction by fuzzy inference, and substantially the same effect as described above can be achieved.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an example in which a hot water temperature control device according to the present invention is applied to a gas instantaneous water heater. This gas instantaneous water heater includes a heat exchanger 10, which is supplied from a water supply (not shown) via a water supply pipe 11 in response to combustion gas from at least one of the gas burners 20, 30. The heated water is heated to produce hot water and supply pipe 12
Supply within. In FIG. 1, reference numeral 10a indicates an inner trunk.

The gas burner 20, based on the ignition energy from the ignition plug 40, the original solenoid on-off valve SV0, the proportional solenoid valve PSV, the solenoid switching valve SV1, and the gas supply pipe 20.
A gas supplied from a gas supply source (not shown) is ignited and burned through a. On the other hand, the gas burner 30 is
Based on the ignition energy from 0, the gas supplied from a gas supply source (not shown) is ignited and combusted through the original solenoid valve SV0, the proportional solenoid valve PSV, the two solenoid switching valves SV1, SV2, and the gas supply pipe 30a. The fan 50 is driven by its fan motor 50a to
Blow toward 0 and 30. The mixing valve 60 is
Driven by the valve motor 60a, the hot water from the supply pipe 12 is mixed with the water supplied from the tap water through the upstream part of the water supply pipe 11 and the branch pipe 13 according to the degree of mixing to obtain hot water at a desired temperature. The hot water is discharged from the hot water pipe 14.

The flow sensor 70 detects the amount of water supplied from the water supply to the water supply pipe 11, and generates a flow pulse signal at a frequency proportional to the detected amount. The rotation speed sensor 80 detects the rotation speed of the fan motor 50a and generates a rotation speed pulse signal at a frequency proportional to the rotation speed. Each of the water temperature sensor 90a, the inner body temperature sensor 90b, and the tap water temperature sensor 90c is composed of a thermistor.
The temperature of the water supplied from the water supply into the upstream portion of the first water sensor is detected and generated as a water temperature detection signal. The inner body temperature sensor 90b detects the temperature of the hot water flowing from the heat exchanger 10 into the supply pipe 12, and generates an inner body temperature detection signal. Hot water temperature sensor 90c
Detects the temperature of the hot water supplied from the mixing valve 60 into the hot water pipe 14 and generates it as a hot water temperature detection signal.

The microcomputer 100 includes a flow rate sensor 70, a rotation speed sensor 80, a water temperature sensor 90a, and an inner body temperature sensor 90 in accordance with flowcharts shown in FIGS.
b and the tapping temperature sensor 90c to execute a computer program. During this execution, the original solenoid on-off valve SV0, the proportional solenoid valve PSV, and the two solenoid switching valves S
Each valve drive circuit 110, 120 and 1 for V1, SV2
3, various arithmetic processes required for controlling the drive of the igniter IG for the spark plug 40 and the motor drive circuits 140 and 150 for the fan motor 50a and the valve motor 60a. However, the computer program is stored in the ROM of the microcomputer in advance.

In this embodiment, the degree of mixing of the mixing valve 60 is basically controlled by PD control. However, the proportional gain K used in PD control is
Since the p and the differential gain Kd usually take constants, depending on the PD control, the mixing degree of the mixing valve 60 can be adjusted to hunting or other unfavorable conditions in accordance with all of the various use conditions of the gas instantaneous water heater. It is difficult to properly control with good responsiveness without causing a phenomenon. Therefore, in this PD control, the proportional gain K
It is necessary to substantially change p and the differential gain Kd so as to correspond to all of the various use conditions of the gas instantaneous water heater.

On the other hand, in this embodiment, the proportional gain Kp and the differential gain Kd are left as they are, the correction value α of these gains is obtained by fuzzy inference, and the respective gains Kp and Kd are corrected by the correction value α. By doing so, a substantial change in each of the above-described gains Kp and Kd is ensured. Therefore, prior to the description of the execution of the arithmetic routine 290, in determining the correction value α, the difference (hereinafter, referred to as a temperature deviation e) between the set temperature and the tapping temperature of the tapping water from the mixing valve 60 into the tapping pipe 14 and the tapping temperature. A method of creating a series of control rules required for fuzzy inference in relation to the amount of hot water (hereinafter, referred to as a hot water amount q) and a result of the creation will be described.

In this embodiment, the antecedent of each control rule is in the state of the temperature deviation e and the amount of hot water q, and the consequent of each control rule is the weight Wi (i) for each antecedent. =
1, 2, ..., 9). In such a case, the temperature deviation e
Mixing valve 60a depending on the size of the hot water and the amount of hot water q
It is necessary to increase or decrease the amount of rotation of. Therefore, the value of each weight Wi is determined experimentally in response to this need. Further, in preparing these control rules, a membership function of a pattern and a number for appropriately determining the correction value α with good responsiveness corresponding to all of various use conditions of the gas instantaneous water heater is required. You.

In this embodiment, five membership functions Fneb and Fneb of each pattern as shown in FIG.
Fnem, Fnes, Fpes, Fpem and Fpeb
Is introduced in relation to the temperature deviation e, and three membership functions Fp of each pattern as shown in FIG.
qs, Fpqm and Fpqb were introduced in relation to the tapping quantity q.

Based on the above, the following control rules were created.

Control Rule Antecedent Consequent U1 e = pes or nes and q = cqs W1 = 0.5 U2 e = pes or nes and q = cqm W2 = 0.8 U3 e = pes or nes and q = cqb W3 = 1.0 U4 e = pem or nem and q = cqs W4 = 0.7 U5 e = pem or nem and q = cqm W5 = 1.3 U6 e = pem or nem and q = cqb W6 = 1. 3 U7 e = peb or neb and q = cqs W7 = 1.1 U8 e = peb or neb and q = cqm W8 = 1.2 U9 e = peb or neb and q = cqb W9 = 1.5 neb, nem, nes, pes, pe
m, peb, pqs, pqm and pqb are respectively
Indicates the following:

Neb: Temperature deviation e is negative and large. Nem: Temperature deviation e is negative and medium. Nes: Temperature deviation e is negative and small. Pes: Temperature deviation e is positive and small. Pem: Temperature deviation. e is positive and medium. peb: Temperature deviation e is positive and large. pqs: Pouring volume q is positive and small. pqm: Pouring volume q is positive and medium. pqb: Pouring volume q is positive. Also, the fitness of either of the two membership functions Fneb and Fpeb, and the two membership functions Fnem and Fneb
The fit of any of pem and the fit of either of the membership functions Fnes and Fpes is ceb, cem and ces, respectively, and the fitness of each of the membership functions Fpqs, Fpqm and Fpqb is Assuming that cqs, cqm, and cqb, respectively, the correction value α is given by the following equation 1.

[0020]

Α = ces (cqs · W1 + cqm · W2 + cqb · W3) + cem (cqs · W4 + cqm · W5 + cqb · W6) + ceb (cqs · W7 + cqm · W8 + cqb · W9) The actual degree of mixing of the mixing valve 60 is Target rotation amount R of the valve motor 60a required for
Is given by Equation 2 representing the following PD control equation.

[0021]

R = α (Kp · e + Kd · de) where, in Equation 2, the symbol de denotes the mixing valve 6
It represents the temperature gradient of the hot water tapping temperature from 0 (represented by the difference between the current tapping temperature and the previous tapping temperature). Further, each of the above membership functions Fneb, Fnem, Fnes, Fpes,
Fpem, Fpeb, Fpqs, Fpqm and Fpq
b, the respective control rules U1 to U9, and both equations 1 and 2 are stored in the ROM of the microcomputer 100 in advance.

In this embodiment configured as described above,
Water is supplied from the water supply into the gas instantaneous water heater through the water supply pipe 11 and the apparatus of the present invention is operated. Then, the flow rate sensor 70 generates a flow rate pulse signal according to the flow rate of water into the water supply pipe 11, and the microcomputer 100 starts executing the computer program in step 200 according to the flowcharts of FIGS. 2 and 3; In step 210, initialization processing is performed, and in the next step 220, “YES” is determined based on the flow rate pulse signal from the flow rate sensor 70. Next, the microcomputer 100 performs arithmetic processing for igniting the ignition plug 40 in the ignition processing routine 230, and in response, the igniter IG causes the ignition plug 40 to ignite.

When the ignition processing of the ignition plug 40 is completed in this way, the microcomputer 100 repeatedly executes the arithmetic processing after step 240 of the computer program as follows. That is, the microcomputer 1
00 calculates the amount of water to be supplied into the water supply pipe 11 based on the flow rate pulse signal from the flow rate sensor 70 at step 240, and determines the rotation speed of the fan motor 50 a according to the rotation speed pulse signal from the rotation speed sensor 80. Is calculated. Then, the microcomputer 100 executes the next step 25.
0, the water temperature detection signal from the water temperature sensor 90a, the inner body temperature detection signal from the inner body temperature sensor 90b, and the tap water temperature sensor 9
Each level of the hot water temperature detection signal from 0c is digitally converted into a feed water temperature, an inner body temperature, and a hot water temperature.

At this stage, if the water supply amount in step 240 is less than the fire extinguishing flow rate, the microcomputer 10
0 determines "NO" in step 260, and in the next step 260a, performs arithmetic processing for extinguishing the ignition plug 40, and in response, the igniter IG sets the ignition plug 4
Extinguish 0. On the other hand, if the determination in step 260 is “YES”, the microcomputer 10
0 calculates the feedforward amount and the feedback amount of the output current to the solenoid proportional valve PSV in step 270 according to the water supply amount in step 240 and the water supply temperature, the inner body temperature and the tap water temperature in step 250.

When the arithmetic processing in step 270 is completed in this way, the microcomputer 100
A target value of an output current to the solenoid proportional valve PSV (hereinafter, referred to as a target output current) is determined based on the sum of the feedforward amount and the feedback amount obtained in step 270,
The target rotation speed of the fan motor 50a is determined based on the rotation speed and the target output current in step 240. Further, the microcomputer 100 executes the step 280
, Based on the target output current, both solenoid switching valves PSV
1. Performs switching processing of the PSV2 and performs processing necessary for opening the original solenoid on-off valve VS0.

After that, the microcomputer 100
The computer program proceeds to the next calculation routine 290 (see FIGS. 3 and 4) for controlling the mixing degree of the mixing valve. Thus, in this calculation routine 290, the microcomputer 100
At 91, a difference between the set temperature (hereinafter, referred to as set temperature TS) and the tapping temperature at step 250 (hereinafter, referred to as tapping temperature Tn) is calculated as a temperature deviation e.
Is calculated as the temperature gradient de between the tapping temperature Tn and the previous tapping temperature Tn-1. However, the set temperature TS is stored in the ROM of the microcomputer 100 in advance.

Next, the microcomputer 100
At step 292, each membership function Fneb,
Fnem, Fnes, Fpes, Fpem and Fpeb
(See FIG. 5 (A).) Based on at least one of the fitness values ces and ce according to the temperature deviation e in step 291.
At least one of m and ceb is determined. For example, e
Assuming that − = 2.5, as shown in FIG. 5A, ceb = 0.25 in relation to the membership function Fneb
And the membership function Fnem
Is obtained as cem = 0.75. In addition,
The other goodness of fit in relation to the temperature deviation e = -2.5 is zero.

After that, the microcomputer 130
At step 293, each membership function Fpqs,
Based on at least one of Fpqm and Fpqb (see FIG. 5 (B)), the water supply amount (hot water amount q
, Cqs, cqm and cqb
Determine at least one of For example, assuming that the amount of hot water q = 4, as shown in FIG. 5B, cqm = 0.5 in relation to each of the membership functions Fpqs and Fpqb.
And cqb = 0.5. In addition, hot water quantity q =
The other goodness of fit in relation to 4 is zero.

Thus, the microcomputer 100
In step 294, at least one of the control rules U1 to U9 is selected based on the temperature deviation e and the amount of hot water q, and at least one of the weights W1 to W9 is determined. For example,
Assuming that the temperature deviation e = −2.5 and the tapping amount q = 4, e =
neb and e = nem, and q = pqm and q = pq
b holds. Therefore, each control rule U5, U6, U8 and U9 is selected, and each weight W5, W6, W8 and W9 is determined.

Next, the microcomputer 100
In step 295, a correction value α is calculated based on the equation (1). For example, as described above, ceb = 0.25, cem =
0.75, cqm = 0.5 and cqb = 0.5, W5 =
If 1.3, W6 = 1.3, W8 = 1.2 and W9 = 1.5, α = 0.75 (0.5 · 1.3 + 0.5 · 1.
3) +0.25 (0.5 · 1.2 + 0.5 · 1.5) =
2.375. After that, the microcomputer 10
0 is calculated in step 296 based on equation 2 in step 29
The target rotation amount R of the valve motor 60a is calculated according to the temperature deviation e and the temperature gradient de at 1 and the correction value α at step 295.

When the operation of the operation routine 290 is completed in this way, the microcomputer 100
In step 300, the target output current and the target rotation speed in step 280 are generated as a current output signal and a rotation speed output signal, respectively.
A switching output signal for switching at least one of SV2 and an opening output signal for opening the original solenoid on-off valve PSV0 are generated, and the target rotation amount in step 296 is generated as a target rotation amount output signal.

Then, the original electromagnetic on-off valve PSV0 is driven and opened by the valve driving circuit 110 in response to the opening output signal from the microcomputer 100, and the electromagnetic proportional valve PSV0 is opened.
V is driven by the valve drive circuit 120 in response to a current output signal from the microcomputer 100, and is opened at an opening corresponding to the target output current. In addition, at least one of the electromagnetic switching valves PSV1 and PSV2 is driven and opened by the valve driving circuit 130 in response to the switching output signal from the microcomputer 100, and the fan 50
Is driven by a motor drive circuit 140 in response to a rotation speed output signal from the microcomputer 100 by the fan motor 50a to blow air toward both the gas burners 20 and 30. Further, the valve motor 60a is driven and rotated by the motor drive circuit 150 in response to the target rotation amount output signal from the microcomputer 100, and accordingly, the mixing valve 60 adjusts the degree of mixing to the target of the valve motor 60a. Change the degree of mixing according to the amount of rotation.

Thus, the original solenoid on-off valve SV0, the solenoid proportional valve PSV and the two solenoid switching valves S
The gas supplied from at least one of V1 and SV2 to the at least one of the two gas burners 20 and 30 from the gas supply source burns under the ignition of the ignition plug 40 and the blowing from the fan 50, and the heat exchanger 10 The water from the water supply pipe 11 is heated by the heat exchange action with the combustion energy to generate hot water and supply the hot water into the supply pipe 12. Then, the mixing valve 60
However, according to the control degree of mixing, the hot water from the supply pipe 12 is mixed with the water from the branch pipe 13 and the hot water of the tapping pipe 14 is set as hot water of the set temperature.
Through the hot water.

As described above, in this embodiment, the correction value α is obtained by fuzzy inference in relation to the temperature deviation e and the amount of hot water q based on each of the membership functions, each control rule, and Equation 1. The target rotation amount R of the valve motor 60a is obtained by correcting (Kp · e + Kd · de) as shown in Expression 2 with the correction value α, and the degree of mixing of the mixing valve 60 is controlled in accordance with the target rotation amount R. . In other words, even if the use conditions of the gas instantaneous water heater change in various ways, according to each change state of the temperature deviation e and the amount of hot water q, the fuzzy inference based on each membership function, each control rule and Equation 1 (Kp 量 e + Kd ・ de) is corrected by a correction value α determined in good response to various changes in the operating conditions of the gas instantaneous water heater, and the target rotation amount R is obtained.
Control the degree of mixing. Accordingly, the proportion of the mixing valve 60 is controlled by the proportional differential operation by changing the proportional gain Kp and the differential gain Kd substantially responsively to various changes in the operating conditions of the gas instantaneous water heater with good responsiveness. As a result, the tapping temperature can be quickly controlled to the set temperature and the hunting of the tapping temperature can be reliably prevented regardless of the use condition of the instantaneous gas water heater.

In the above-described embodiment, the proportional gain Kp and the differential gain Kd are corrected by the correction value α. Instead, (Kp · e + Kd · d)
e) That is, the valve motor 6 obtained by the proportional differential operation formula
The rotation amount 0a may be corrected using the correction value α.

In practicing the present invention, Kd · de may be omitted from the equation (2).

In practicing the present invention, as in the previous embodiment, the combination of the proportional differential operation and the correction value .alpha.
Instead of obtaining the rotation amount R of 0a, the rotation amount R may be directly obtained by fuzzy inference according to each change of the temperature deviation e and the tapping amount q.

In the above-described embodiment, the correction value α for correcting the proportional gain Kp and the differential gain Kd is determined by fuzzy inference. Instead, the proportional gain Kp and the differential gain Kd may be determined by the temperature deviation e. It may be carried out so as to be changed in accordance with each change of the hot water amount q.

In implementing the present invention, the number of the control rules U1 to U9 for obtaining the correction value α and the membership functions may be appropriately changed and implemented as necessary. The values of the weights Wi in the rules U1 to U9 may also be changed as appropriate.

In practicing the present invention, the flow rate sensor 70 may be provided in the tapping pipe 14 or in the upstream part of the water supply pipe 11 instead of the water supply pipe 11.

In practicing the present invention, the present invention is not limited to a gas instantaneous water heater, but may be applied to, for example, controlling the temperature of hot water from a mixing valve of a water heater utilizing electric energy or solar energy. May be.

[Brief description of the drawings]

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

FIG. 2 is a first part of a flowchart showing the operation of the microcomputer of FIG. 1;

FIG. 3 is a latter part of the flowchart.

4 is a detailed flowchart of a mixing valve mixing degree control calculation routine of FIG. 3;

FIG. 5 is a pattern diagram showing the relationship between the degree of fitness of each membership function, the temperature deviation, and the amount of hot water.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Heat exchanger, 20, 30 ... Gas burner, 60 ... Mixing valve, 60a ... Valve motor, 70 ... Flow rate sensor, 90c ... Hot water temperature sensor, 100 ... Microcomputer.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-44106 (JP, A) JP-A-62-123513 (JP, A) JP-A-4-71009 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) F24D 17/00 F24H 1/10 302

Claims (2)

(57) [Claims] 1. Heat exchange means for heating water from a water supply source in accordance with heat energy from a heat energy supply source to generate hot water, and heat water from the heat exchange means and water from the water supply source. Mixing means for mixing according to the degree of mixing, in a water heater configured to discharge hot water from the mixing means, a hot water temperature detecting means for detecting a hot water temperature of the hot water from the mixing means; and the heat exchange means or a tapping amount detecting means for detecting the volume of the melt teemed from the mixing means, before the setting of the hot water to be tapped
Control means for controlling the degree of mixing of the mixing means so as to quickly reach the set temperature of the hot water in accordance with at least one of the temperature deviation which is the difference between the detected hot water temperature and the detected hot water amount. A hot water temperature control device for a water heater, wherein 2. The arithmetic means for performing a proportional operation or a proportional differential operation on the degree of mixing of the mixing means so that the hot water temperature reaches a set temperature in accordance with a change in the detected hot water temperature. the arithmetic degree of mixing by, and a correction means for correcting the fuzzy inference in accordance with the change in at least one of the detected tapping amount and the detected tapping temperature, mixing of the mixing means towards the correct degree of mixing of the correction means The hot water temperature control device for a water heater according to claim 1, wherein the degree is controlled.