KR940004184B1 - Combustion control device of how water feeder - Google Patents

Abstract

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Description

Combustion amount control device of hot water heater

1 is a block diagram showing a configuration of the present invention.

2 is a schematic configuration diagram of a bypass mixed gas water heater to which the present invention is applied.

3 is a schematic block diagram of a combustion amount control apparatus of a hot water heater according to an embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

10: combustion unit 13: blower

15: feed forward combustion amount calculation means

16: heat exchange capacity correction combustion amount calculation means

17: air-fuel ratio correction combustion amount calculation means 18: proportional correction combustion amount calculation means

19: integral correction combustion amount calculation means 31: heat exchanger

40: controller

The present invention relates to a combustion amount control apparatus for a hot water heater, which controls the combustion amount of the hot water heater.

Since the blower which supplies combustion air to a combustion chamber is equipped with the rotating body with a large mass, a rotation speed cannot change rapidly. On the other hand, a fuel regulator (for example, a proportional valve) for supplying fuel to the combustion chamber can easily change the supply amount of fuel because the mass of the valve body is small. For this reason, if the blower and the fuel regulator are controlled independently, or the fuel regulator and the blower are controlled at the same time, the fuel supply amount and the air flow amount of the blower are not suitable when the amount of combustion changes, which causes abnormality in the air-fuel ratio.

Therefore, the air volume of the blower is controlled according to the amount of combustion, and the opening degree of the fuel regulator is controlled according to the air volume and the combustion state (air ratio) of the blower to prevent abnormality of the air-fuel ratio when the amount of combustion changes. A hot water heater is devised (Japanese Patent Laid-Open No. 62-252826).

In addition, the conventional combustion amount is calculated by the feedforward control based on the set temperature, the inlet temperature, the quantity, and the thermal efficiency so that the hot water of the set temperature set by the user can be obtained.

However, if the combustion amount is changed by the feedforward control, such as when the set temperature is changed, or when the inlet temperature and the quantity are changed, the influence of the residual heat amount due to the heat capacity of the heat exchanger exchanging heat and water passing through the combustion. As a result, the tapping temperature set by the user is not obtained until the heat exchanger reaches the thermal equilibrium.

In addition, since the control of the air-fuel ratio is performed by the amount of fuel supplied, when the amount of fuel supplied by the air-fuel ratio correction changes, the amount of heat obtained is changed. For this reason, the tapping temperature set by the user may not be obtained by the air-fuel ratio correction.

That is, determining the combustion amount only by the conventional feedforward control has a problem that the tapping temperature set by the user cannot be obtained due to each error.

The present invention has been made to eliminate the above-mentioned drawbacks, and an object thereof is to provide a combustion amount control device of a hot water heater, which can always supply a hot water according to a set temperature.

In order to achieve the above object, the present invention provides a hot water heater including a combustion unit for burning fuel, a blower for supplying combustion air to the combustion unit, and a heat exchanger for heating water by heat-exchanging heat and water obtained by combustion of the fuel. In the combustion amount control apparatus of the hot water heater, which controls the amount of combustion by controlling the amount of air blown by the blower, the difference between the temperature Ts set by the controller and the inlet temperature Ti detected by the inlet temperature sensor and quantity detection Feedforward combustion amount calculating means for calculating a feedforward combustion amount required to maintain the tapping temperature at a set temperature by multiplying the quantity W detected by the sensor with the heat exchange efficiency l / eff of the heat exchanger; The difference between the set temperature Ts set by the controller and the tapping temperature To detected by the tapping temperature sensor, the heat capacity M preset in the heat exchanger, and the bypass ratio between the heat exchanger and the bypass channel. Heat exchange capacity corrected combustion amount calculating means for multiplying the constant (a) according to the result and calculating a heat exchange capacity corrected combustion amount; An air-fuel ratio corrected combustion amount calculating means for correcting an amount of gas increased or decreased in accordance with the air-fuel ratio correction by inverting the sign of the air-fuel ratio corrected combustion amount N to calculate an air-fuel ratio corrected combustion amount when the air-fuel ratio is corrected by the controller; The difference between the set temperature Ts set by the controller and the tapping temperature To detected by the tapping temperature sensor, the water quantity W detected by the water quantity detection sensor, and the proportional constant E are multiplied. Proportionally corrected combustion amount calculating means for calculating a corrected combustion amount; Integral correction combustion amount calculating means for calculating an integral correction combustion amount by integrating the difference between the set temperature Ts set by the controller and the tapping temperature detected by the tapping temperature sensor; The feed forward combustion amount, the heat exchange capacity correction combustion amount, the air-fuel ratio correction combustion amount, the proportional correction combustion amount, the integral correction combustion amount is determined by adding the calculated feed forward combustion amount calculated by the respective means to control the combustion amount of the hot water heater. By means.

The present invention having the above configuration adds the proportionally corrected combustion amount and the integral correction combustion amount to the pisword combustion amount. As a result, the combustion amount obtained is a correction of the error between the feedforward combustion amount and the actual combustion amount.

By adding the heat exchange capacity corrected combustion amount to the combustion amount obtained by adding the feed forward combustion amount, the proportional correction combustion amount and the integral correction combustion amount, the residual heat content amount due to the heat capacity of the heat exchanger is corrected. As a result, even if the heat exchanger reaches the thermal equilibrium, the tapping temperature set by the user can be obtained.

Further, by adding the air-fuel ratio correction combustion amount to the combustion amount obtained by adding the feedforward combustion amount, the proportional correction combustion amount, the integral correction combustion amount, and the heat exchange capacity correction combustion amount, the fuel increased or decreased by the air-fuel ratio correction is previously corrected to the combustion amount. As a result, even if the fuel supply amount is changed by the air-fuel ratio correction, the tapping temperature set by the user can be obtained.

According to the present invention, since the amount of combustion is determined by adding the feedforward combustion amount, the heat exchange capacity correction combustion amount, the air-fuel ratio correction combustion amount, the proportional correction combustion amount, and the integral correction combustion amount, the hot water of the temperature set by the user can be stably supplied.

Next, an embodiment in which the present invention is applied to a bypass mixing hot water heater will be described with reference to the drawings.

Figure 1 is a block diagram showing the configuration of the present invention, Figure 2 is a schematic configuration diagram of the bypass mixing hot water heater in which the present invention is applied, Figure 3 is a schematic diagram of the combustion amount control apparatus of the hot water heater according to an embodiment of the present invention. It is a block diagram.

As shown in Figs. 1 to 3, the gas water heater according to the present invention is divided into a combustion section 10, a gas supply pipe 20, a water supply pipe 30, and control, which perform combustion of fuel in large portions. The apparatus 40 is comprised.

The combustion section 10 is composed of a combustion case 12 having a ceramic surface combustion burner 11 installed therein and a blower 13 for supplying combustion air in the combustion case 12. Air for combustion, which is introduced into the combustion case 12 by (13), is discharged from the exhaust port (not shown) as the combustion gas after combustion.

The gas supply pipe 20 supplies fuel gas to the nozzle 21 opened to the inner circumference of the centrifugal fan 14 of the blower 13, and the source solenoid valve 22 and the kettle valve 23 from the upstream side. ) And proportional valves 24 are provided in this order. The downstream of the proportional valve 24 is divided into two, and the switching solenoid valve 25 is provided in one side, and the orifice 26 is provided in the other. In addition, the solenoid valve 22, the kettle valve 23, and the switching solenoid valve 25 open and close the gas supply pipe 20 by energization control, and the proportional valve 24 changes the aperture ratio according to the energization amount. The amount of gas supplied to the nozzle 21 is adjusted.

One side of the water supply pipe 30 is connected to a supply source of water, and the other side is connected to a hot water supply port. The water supply pipe 30 exchanges heat generated by gas combustion of the burner 11 with water flowing through the interior, and passes through the interior. A heat exchanger 31 for heating water and a bypass channel 32 for bypassing the heat exchanger 31 are provided.

The water supply pipe 30 upstream of the branch path between the heat exchanger 31 and the bypass channel 32 shows the quantity of water introduced even if the water pressure flowing into the heat exchanger 31 and the bypass channel 32 changes. The electric water quantity control device 33 which combines the function and the function of the control valve which keeps constant, and the function of the water quantity control valve which adjusts water quantity is provided. In addition, the bypass channel 32 is provided with a throttle valve (opening and closing valve of the present invention) 34 for controlling the amount of water passing through the bypass channel 32 and opening and closing the bypass channel 32. have.

In addition, the throttle ratio of the electric quantity control device 33 is equal to or less than the throttle valve 34 to regulate the total amount of water flowing into the heat exchanger 31 and the bypass channel 32. It is installed. In addition, the electric quantity control apparatus 33 and the throttle valve 34 drive the valve body which opens and closes a channel as a means of adjusting a quantity of water using a gear motor.

As shown in FIG. 3, the control device 40 is composed of a microcomputer 41, a relay circuit 42, and a drive circuit 43. The controller 44 or various sensors operated by a user are shown. Sparker 45, the original solenoid valve 22, the kettle valve 23, the proportional valve 24, the switching solenoid valve 25, the electric quantity control device which ignites the burner 11 according to the output of 33), the throttle valve 34 is energized.

Various sensors of the control device 40 include a flame rod 46 and a thermocouple 47 for detecting the flame of the burner 11 and an air-fuel ratio, a valve of the electric quantity control device 33 and the throttle valve 34. Potentiometers 48 and 49, which interlock with the sieve, detect the air flow rate, and the air flow rate sensor 50, the heat exchanger 31, and the bypass channel 32 which detect the air volume of the blower 13 by the rotational speed. Water temperature sensor 51 for detecting the temperature of the water flowing into the), the water temperature sensor 52 for detecting the temperature of the water passing through the heat exchanger 31, the heat exchanger 31 and the bypass channel 32 There is a tapping water temperature sensor 53 for passing through and detecting the temperature of the mixed hot water, a heat exchanger 31 and a water quantity detecting sensor 54 for detecting the amount of water flowing into the bypass channel 32.

In addition, the air volume detection sensor 50 includes a rotating body interlocked with the motor of the blower 13 and generates a pulse signal according to the rotation of the rotating body. In addition, the water quantity detection sensor 54 includes a rotating body that rotates in accordance with the flow of water, and generates a pulse signal according to the rotation of the rotating body. Then, the microcomputer 41 detects the rotational speed of the blower 13 or the rotational speed of the rotating body from the interval of the pulse signal generated by the airflow rate sensor 50 and the water quantity detection sensor 54 to detect the airflow rate and the quantity. do.

Next, the combustion control and the quantity control by the microcomputer 41 will be briefly described.

When the user generates a flow of water in the water supply pipe 30 by operating the faucet connected to the hot water inlet, the rotating body in the water quantity detection sensor 54 rotates to start combustion. The amount of combustion after commencement of combustion is determined by the quantity of water obtained by various sensors, the temperature of inlet obtained by various sensors, the temperature of the hot water passing through the heat exchanger 31, the mixing hot water temperature (the hot water temperature), and the like so as to obtain a set temperature set by the controller 44. And the blower 13 is voltage-controlled so that the air volume according to the combustion amount may be supplied to the burner 11. That is, the combustion amount and the applied voltage (air volume) of the blower 13 are in proportional relationship. Then, the proportional valve 24 and the switching solenoid valve 25 are energized so that the amount of gas corresponding to the rotational speed of the blower 13 or the flame temperature of the burner 11 is obtained. In addition, the combustion amount is set so that the temperature of the hot water passing through the heat exchanger 31 is maintained at a temperature (for example, 60 ° C) at which water (drainage) generated by combustion does not adhere to the heat exchanger 31.

The throttle valve 34 is fixed to an appropriate opening degree calculated from the inlet temperature, the set temperature, the hot water temperature passed through the heat exchanger 31, and the hot water temperature. This fixing is set such that the flow rate flowing through the bypass water passage 32 is twice the amount of water flowing through the heat exchanger 31. In other words, the ratio of the flow resistance between the bypass channel 32 and the heat exchanger 31 is approximately 2: 1 by the throttle valve 34. In addition, the fixing of the opening degree of the throttle valve 34 is released when the water supply amount is small or when the tapping temperature is lowered, so that the throttle valve 34 is opened so that the opening degree calculated according to the water supply amount and tapping temperature is adjusted. Energized control.

The electric flow rate controller 33 is energized so as not to exceed the maximum flow rate required for obtaining the tapping temperature.

Next, the control apparatus of the combustion amount is explained in full detail.

The combustion amount Q adds the feedforward combustion amount FF, the heat exchange capacity correction combustion amount K, the air-fuel ratio correction combustion amount T, the proportional correction combustion amount P, and the integral correction combustion amount I,

Q = FF + K + T + P + 1

It is expressed by the formula

The feedforward combustion amount FF is calculated by the feedforward combustion amount calculation means 15, and the heat exchange capacity correction combustion amount K is calculated by the heat exchange capacity correction combustion amount calculation means 16, and the air-fuel ratio correction combustion amount T is calculated. Is calculated by the air-fuel ratio correction combustion amount calculating means 17, the proportional correction combustion amount P is calculated by the proportional correction combustion amount calculating means 18, and the integral correction combustion amount I is calculated by the integral correction combustion amount calculating means 19. Is calculated. Then, the feed forward combustion amount calculating means 15, the heat exchange capacity corrected combustion amount calculating means 16, the air-fuel ratio correction combustion amount calculating means 17, the proportional correction combustion amount calculating means 18, the integral correction combustion amount calculating means 19 Are each embedded in the microcomputer 41, and each performs calculation independently.

The pod forward combustion amount FF is the difference between the set temperature Ts set by the controller 44 and the intake temperature Ti detected by the intake temperature sensor 51 and the quantity detected by the quantity detection sensor 54. (W) is calculated by multiplying the heat exchange efficiency (I / eff) of the heat exchanger 31 by the feedforward combustion amount calculating means 15.

This is represented by the formula FF = (Ts-Ti) W / eff.

The heat exchange capacity corrected combustion amount K is the difference between the set temperature Ts set by the controller 44 and the tapping temperature To detected by the tapping temperature sensor 53, and the heat exchanger used. 31 is calculated by multiplying the heat capacity M set in advance and the constant a according to the bypass ratio between the heat exchanger 31 and the bypass channel 32 by the heat exchange capacity corrected combustion amount calculating means 16.

This is represented by the formula K = a (Ts-To) M.

The calculation of the heat exchange capacity correction combustion amount K calculates the virtual temperature Te of the heat exchanger 31 necessary for obtaining the set temperature Ts set by the controller 44, and the virtual temperature Te. The difference between the hot water temperature Tm detected by the hot water temperature sensor 52 and the heat capacity M may be calculated. This is represented by the formula K = (Te-Tm) M.

When the air-fuel ratio corrected combustion amount T is corrected by the controller 44, the air-fuel ratio corrected combustion amount is calculated by correcting the amount of gas that is increased or decreased according to the air-fuel ratio correction and inverting the sign of the corrected combustion amount N by the air-fuel ratio correction. Inverted by means 17.

This is represented by the formula T = -N.

The calculation of the proportional correction combustion amount P is detected by the difference between the set temperature Ts set by the controller 44 and the tapping temperature To detected by the tapping temperature sensor 53 and the quantity detecting sensor 54. The calculated quantity W is multiplied by the proportional correction combustion amount calculating means 19 and calculated.

This is represented by the formula P = E (Ts-To) W.

Moreover, (Ts-To) W represents the deviation value by the change of quantity. In this embodiment, around E = 0.8 is appropriate.

The calculation of the integral correction combustion amount I is performed by calculating the difference Ts-To between the set temperature Ts set by the controller 44 and the tapping temperature To detected by the tapping temperature sensor 53. Integral in (19).

This is represented by the formula In = I _n-1 + bWn (Ts-To). Here, bxWn represents an integral constant, In is an integral correction combustion amount calculated this time, and I _n-1 is an integral correction combustion amount calculated last time. By proportionating the change amount of the integral correction combustion amount I with the flow rate Wn, the time delay necessary for the feedback is corrected, so that the integral correction combustion amount I can be uniformly evaluated throughout the quantity. In addition, the integral correction combustion amount I may be an integral of the FF value and the change ratio, and after the rational evaluation of the calculated integral value is reasonably evaluated, the change may be corresponded.

In the formula of the combustion amount, Q = FF + K + T + P + I, P + I corrects the combustion error from the tapping temperature, and by setting it to FF + P + I, the error of the combustion amount determined by the feedforward can be suppressed. .

In addition, since the remaining heat amount due to the heat capacity of the heat exchanger 31 is corrected by adding the heat exchange capacity corrected combustion amount K to the FF + P + I, the user sets even when the heat balance of the heat exchanger 31 is reached. One tapping temperature can be supplied to the user.

Further, by adding the air-fuel ratio correction combustion amount T to the FF + K + P + I, the gas increased or decreased by the air-fuel ratio correction is corrected to the combustion amount in advance, so that even if the gas supply amount is changed by the air-fuel ratio correction, the user sets The tapping temperature can be supplied to the user.

As described above, the combustion amount is Q = FF + K + T + P + I so that the tapping temperature set by the user can always be stably supplied.

In addition, although the maximum amount of combustion and the minimum amount of combustion are limited depending on the capacity of the hot water heater, even if the amount of combustion Q is outside the range of the maximum amount of combustion and the minimum amount of combustion, each feedforward amount of combustion FF and the amount of heat exchange capacity correction combustion amount K ), The air-fuel ratio correction combustion amount T, the proportional correction combustion amount P, and the integral correction combustion amount I are executed by the microcomputer 41.

Moreover, in order to apply the voltage according to the amount of combustion to a blower, you may calculate the amount of combustion directly as calculation of a voltage. That is, the voltage applied to the blower adds the voltage obtained by the feed forward, the voltage obtained by the heat exchange capacity correction, the voltage obtained by the air-fuel ratio correction, the voltage obtained by the proportional correction, and the voltage obtained by the integral correction. Was obtained.

In addition, although the water heater provided with the bypass channel was mentioned as an example, you may apply this invention to the water heater which does not have a bypass channel.

Moreover, although the example which used gas for fuel was mentioned, you may apply to the hot water heater using liquid fuel, such as kerosene and heavy oil.

Claims (1)

A hot water heater comprising a combustion section for burning fuel, a blower for supplying combustion air to the combustion section, and a heat exchanger for heating water by heat-exchanging heat and water obtained by combustion of the fuel, the amount of blowing of the blower is controlled. In the combustion amount control device of the hot water heater, which controls the combustion amount, the difference between the set temperature Ts set by the controller and the inlet temperature Ti detected by the inlet temperature sensor, and the quantity of water detected by the quantity sensor Feed forward combustion amount calculating means for calculating the feedforward combustion amount required to maintain the tapping temperature at the set temperature by multiplying the heat exchange efficiency (l / eff) of the heat exchanger; The difference between the set temperature Ts set by the controller and the tapping temperature To detected by the tapping temperature sensor, the heat capacity M preset in the heat exchanger, the heat exchanger and the bypass channel and the bypass ratio Heat exchange capacity corrected combustion amount calculating means for multiplying constant (a) to calculate heat exchange capacity corrected combustion amount; An air-fuel ratio corrected combustion amount calculating means for correcting an amount of gas that is increased or decreased in accordance with the air-fuel ratio correction by inverting the sign of the air-fuel ratio corrected combustion amount N to calculate an air-fuel ratio corrected combustion amount when the air-fuel ratio is corrected by the controller; The difference between the set temperature Ts set by the controller and the tapping temperature To detected by the tapping temperature sensor, the amount W detected by the quantity detecting sensor, and the proportional constant E are multiplied. Proportionally corrected combustion amount calculating means for calculating a corrected combustion amount; Integral correction combustion amount calculating means for calculating an integral correction combustion amount by integrating the difference between the set temperature Ts set by the controller and the tapping temperature detected by the tapping temperature sensor; The amount of combustion is determined by adding the feedforward combustion amount, the heat exchange capacity correction combustion amount, the air-fuel ratio correction combustion amount, the proportional correction combustion amount, and the integral correction combustion amount calculated by the respective means to control the combustion amount of the hot water heater. Combustion amount control device.

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