JPH05133602A - Combustion controller - Google Patents

Abstract

PURPOSE:To supply hot water at a constant temperature by calculating the quantity of feedforward of a burner based on the temperature of the supply water on the side of the inlet or the volume of supplied water of a heat exchanger and correcting the feedback by the temperature of the supply hot water at the outlet of the heat exchanger and, at the same time, stopping the correction of feedback for a specified time after starting the supply of hot water. CONSTITUTION:A control device C receives the temperature of incoming water from a water temperature thermistor S1, temperature on the downstream side of a heat exchanger 2 from a hot water temperature thermistor S2, volume of flowing water per unit time through the heat exchanger 2 from a flow rate sensor 4, and the temperature of delivered hot water of a delivered hot water channel W4 from a delivered hot water temperature thermistor S3. And a burner 3 is controlled by an isolation valves 9, l0, regulating valve 11, ignition plug 15, and two-way valve 5 so as to satisfy set conditions, and a later boiling mode and ordinary mode are controlled. Namely, the control device C opens a hot water supply cock 1 and gives ignition if not ignited, and carries out the late boiling mode or ordinary mode based on the difference of the temperature of delivered hot water and a target temperature when a certain time has passed after ignition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided with a heat exchanger for heating water, a burner for heating the heat exchanger, and control means for controlling the combustion amount of the burner. The combustion amount of the burner is feedforward-calculated based on the feedwater temperature or the feedwater amount on the inlet side of the heat exchanger, and is feedback-corrected based on the hot water temperature on the outlet side of the heat exchanger. The present invention relates to a combustion control device.

[0002]

2. Description of the Related Art Generally, the burner combustion amount can be expressed by an arithmetic expression with the amount of water supplied and the temperature of water supplied as variables. In addition, the feedforward calculated value is obtained as a proportional value with respect to the water supply amount and the difference between the target hot water supply temperature and the water supply temperature. On the other hand, the feedback correction value is obtained as the sum of the integral value and the proportional value of the difference between the target hot water supply temperature and the actual hot water supply temperature. Conventionally, in the above-described combustion control device, the burner combustion amount has always been calculated by the same arithmetic expression.

[0003]

At the start of tapping, a so-called "cold water sandwich phenomenon" may occur in which the hot water supply temperature becomes hot or dull. Here, in the case where the burner combustion amount is always obtained by the same arithmetic expression as in the above-mentioned conventional technique, the burner combustion amount becomes a small value when hot water having a temperature higher than the target hot water supply temperature comes out due to post-boiling. And
Even if the effect of after-boiling becomes small and the hot water temperature becomes low, the integrated value of the feedback correction value is a negative value, so the combustion amount of the burner continues to be a small value for a while. In other words, in the above-mentioned conventional technique, when hot water having a temperature higher than the target hot water supply temperature comes out due to post-boiling, the hot water supply temperature is largely lowered than the target hot water supply temperature as a reaction. An object of the present invention is to eliminate the above-mentioned conventional drawbacks and to obtain a combustion control device capable of supplying hot water at a stable temperature by reducing fluctuations in hot water temperature even when a post-boiling phenomenon occurs at the start of hot water discharge. is there.

[0004]

In order to achieve this object, the first characteristic configuration of the combustion control device according to the present invention is such that the control means stops the feedback correction for a predetermined time from the start of hot water supply. It is configured to.

In a second characteristic configuration, the control means sets the combustion amount of the burner to a combustion amount smaller than the combustion amount obtained by the feedforward calculation for a predetermined time from the start of hot water supply. It is configured to.

[0006]

The operation of the first characteristic configuration is as follows. Here, the predetermined time is, for example, the time from the start of hot water supply until the hot water staying in the heat exchanger before the hot water supply is started to the outside. That is, by stopping the feedback correction for a predetermined time from the start of hot water supply, even when hot water having a temperature higher than the target hot water supply temperature comes out due to post-boiling, if the effect of post-boiling becomes small and the hot water temperature becomes low, the burner The amount of combustion can be immediately returned to a relatively large value.

The operation of the second characteristic configuration is as follows. When the feedback correction is stopped when hot water having a temperature higher than the target hot water supply temperature comes out due to the post-boiling, the correction for reducing the burner combustion amount is not performed. Therefore, by setting the feedforward calculated value to a small value, it is possible to prevent the combustion amount of the burner from becoming large when hot water having a temperature higher than the target hot water supply temperature is discharged.

[0008]

According to the first characteristic structure, when the influence of after-boiling becomes small and the temperature of the hot water becomes low, the combustion amount of the burner can be immediately returned to a relatively large value. Can be suppressed from falling below the target hot water supply temperature.

In the second characteristic configuration, the combustion amount of the burner is suppressed from becoming large when hot water having a temperature higher than the target hot water supply temperature is discharged, so that the hot water affected by the post-boiling is further heated. It can prevent it from getting hot.

[0010]

Embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the water heater body A and the water heater body A
A remote controller R that gives a command to the hot water supply valve 1 and a hot water tap 1 are provided.

The water heater body A has a heat exchanger 2 for heating water.
A burner 3 for heating the heat exchanger 2, a spark plug 15, and a controller C are provided. Also, the water inlet 12
A water inlet W1 communicating with the heated passage W2 provided with a heat exchanger 2 for heating water and a bypass W bypassing the heat exchanger 2.
It is branched into 3 and 3. Further, the respective downstream sides of the heated passage W2 and the bypass passage W3 are connected to a hot water outlet W4 communicating with the hot water supply pipe connection port 13. Inlet W1 in Inlet W1
Temperature thermistor S1 for detecting the incoming water temperature Ti supplied to the
However, a flow rate sensor S4 for detecting the water flow rate q of the heat exchanger 2 per unit time and a hot water temperature thermistor S2 for detecting the hot water temperature Ty on the downstream side of the heat exchanger 2 are connected to the bypass path W3 in the heated path W2. A two-way valve 5 is installed in the hot water outlet passage W4, and a hot water outlet temperature thermistor S3 for detecting the hot water outlet temperature To of the hot water outlet passage W4 is provided in the hot water outlet passage W4. In the fuel supply path G1 to the burner 3, electromagnetic shutoff valves 9 and 10 and a control valve 11 for adjusting the fuel supply amount are provided.

The remote controller R is provided with an operation switch 6, a target temperature setting device 8 for setting a target hot water temperature Ts in the hot water outlet W4, and a target hot water temperature display device 7.

The controller C includes a water temperature thermistor S1, a hot water temperature thermistor S2, a hot water temperature thermistor S3, and a flow rate sensor S.
4 and the remote controller R are connected to each other. Then, the control unit C sets the shutoff valves 9, 1 so that the outlet heated water temperature To in the outlet heated water passage W4 becomes the target outlet heated temperature Ts based on the preset information stored and various input information.
0, the control valve 11, the spark plug 15, and the two-way valve 5 are controlled to operate. That is, the control unit 100 is used to control the combustion amount of the burner 3 by using the control unit C.
Is configured.

The control of the burner 3 (hot water temperature control) will be further described. The hot water supply temperature control includes a post-boiling mode and a normal mode. The hot water outlet temperature To is equal to or higher than the sum of the target hot water outlet temperature Ts and the predetermined amount T1, or the post-boiling mode is set until the set time t1 elapses from the start of hot water supply. The heating amount Ip of the burner 3 in the post-boiling mode is obtained based on the equation 1.

[0015]

## EQU1 ## Ip = Ka × (Ts−Ti) × q × t / t1 + Kp × ΔT

Here, ΔT is the target temperature Ts and the heat exchanger 2
The deviations of the hot water temperature Ty on the downstream side of Ka, Kp, and Ki are constants. The set time t1 is calculated based on the equation 2.

[0017]

## EQU00002 ## t1 = K1.times. (To-Ti) .times.Qo / q

Qo is the amount of residual hot water remaining in the heat exchanger 2, K
1 is a constant. The hot water outlet temperature To becomes less than the sum of the target hot water outlet temperature Ts and the predetermined amount T1, or after a lapse of a predetermined time t1 from the start of hot water supply, the normal mode is entered. The heating amount Ip of the burner 3 in the normal mode is obtained based on the equation 3.

[0019]

[Expression 3] Ip = Ka × (Ts−Ti) × q + Kp × ΔT + Ki × ∫ΔTdt

The first term in Equation 3 is a normal feedforward calculation value. On the other hand, the first term in Expression 1 is smaller than the normal feedforward calculation value. That is, the feedforward calculated value in the ignition mode is set to a combustion amount smaller than the combustion amount obtained by the normal feedforward calculated value. The second term and the third term in the equation 3 are normal feedback calculated values. On the other hand, in Equation 1, the third term is omitted.
That is, in the post-boiling mode, part of the feedback correction is stopped.

Next, the operation of the controller C will be described with reference to the flow chart shown in FIG. First, the necessity of hot water supply is determined based on the information of the operation switch 6, and if hot water supply is not required, it is determined whether or not hot water supply is currently being performed. If the hot water is not being supplied until now, it returns as it is. If the hot water is being supplied up to the present, the fire extinguishing process is executed. When it is determined that hot water supply is required, the flow rate sensor S
Based on the information of 4, it is determined whether the hot water tap 1 is open. When the hot water tap 1 is closed, it is determined whether or not hot water is being supplied up to the present time. If hot water is not being supplied up to the present time, the process returns as it is, and if hot water is being supplied up to now, a fire extinguishing process is executed. When it is determined in the above determination that the hot water tap 1 is open, it is determined whether or not the ignition is being performed. If not, the ignition process for igniting the burner 3 is executed. .. Then, the hot water supply temperature control described above is executed. That is, the hot water outlet temperature To is higher than the sum of the target hot water outlet temperature Ts and the predetermined amount [Delta] T, or the predetermined time period t1 has elapsed after ignition. In the after boiling mode, the two-way valve 5
And the two-way valve 5 is closed when shifting to the normal mode.

[Other Embodiments] In the above embodiment, a part of the feedback correction is stopped for a predetermined time from the start of hot water supply, but all the feedback corrections may be stopped.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a block diagram of a control configuration.

FIG. 2 is a flowchart of control operation.

[Explanation of symbols]

 2 heat exchanger 3 burner 100 control means

Claims (2)

[Claims] 1. A heat exchanger (2) for heating water, a burner (3) for heating the heat exchanger (2), and a control means (100) for controlling the combustion amount of the burner (3). And the control means (100) performs a feedforward calculation of the combustion amount of the burner (3) based on the feed water temperature or the feed water amount at the inlet side of the heat exchanger (2), and at the same time, the heat exchanger. (2) A combustion control device configured to perform feedback correction based on the hot water supply temperature on the outlet side, wherein the control means (100) stops the feedback correction for a predetermined time from the start of hot water supply. Combustion control device configured as. 2. The control means (100) sets the combustion amount of the burner (3) to a combustion amount smaller than the combustion amount obtained by the feedforward calculation for a predetermined time from the start of hot water supply. The combustion control device according to claim 1, configured as described above.