JP2557596B2 - Combustion fan controller - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fan for supplying combustion air to a burner, a rotation speed setting means for setting a target rotation speed of the fan based on a combustion amount, and a reference corresponding to the target rotation speed. Reference setting means for setting electric power and control means for controlling drive power of the fan so that the rotation speed of the fan matches the target rotation speed are provided, and the rotation speed setting means sets the reference power and The present invention relates to a combustion fan control device configured to correct the target rotation speed so that the drive power matches the reference power as the deviation from the drive power exceeds a predetermined value.

[0002]

2. Description of the Related Art An initial value of a target rotational speed of a fan is set to a value such that an air-fuel ratio can be maintained at a predetermined value under an ideal condition in which a blowing characteristic can ignore exhaust blockage. However, when exhaust gas is blocked, the air-fuel ratio will fall below a predetermined value even if the fan speed is maintained at the target speed. Therefore, conventionally, as disclosed in Japanese Patent Laid-Open No. 3-186113, a reference electric power corresponding to a target rotation speed is set, and when a deviation occurs between the drive electric power and the reference electric power, exhaust blockage or the like occurs. In some cases, the target rotation speed is corrected so that the driving power matches the reference power when it is determined to have occurred. Here, the reference power is set corresponding to an ideal condition in which the ventilation characteristic is such that exhaust blockage can be ignored, and the set numerical value has not been changed.

[0003]

In the above-mentioned prior art, control is performed so that the same drive power can be obtained if the combustion amount is the same, even when the air blowing characteristics are under ideal conditions or when exhaust gas is blocked. ing. However, the amount of air blown is different between under ideal conditions and when the exhaust gas is blocked, even if the driving power is the same. That is, when the exhaust gas is blocked, the air-fuel ratio falls below a predetermined value. An object of the present invention is to eliminate the above-mentioned conventional drawbacks and obtain a combustion fan control device capable of maintaining the air-fuel ratio at a predetermined value even when exhaust gas blockage or the like occurs.

[0004]

To achieve this object, in a first characteristic configuration of a combustion fan control device according to the present invention, the reference setting means sets a deviation between the reference power and the drive power to a predetermined value. When the value exceeds the value, the reference power is corrected to a value larger by a predetermined amount.

In the second characteristic configuration, the reference setting means is
When the deviation between the drive power and the reference power exceeds a predetermined value, the reference power is corrected to a value smaller by a predetermined amount.

[0006]

The operation of the first characteristic configuration is as follows. When the deviation between the reference power and the driving power exceeds a predetermined value, it can be determined that exhaust blockage or the like has occurred. Therefore, the target rotation speed is corrected to a high value, and the target rotation speed at this time is set so that the driving power becomes a value larger by a predetermined amount than when the blowing characteristic is under the ideal condition. In other words, by increasing the drive power as compared with the ideal condition, the air flow rate equivalent to that under the ideal condition is maintained.

The operation of the second characteristic configuration is as follows. When the deviation between the drive power and the reference power exceeds a predetermined value, it can be determined that the condition such as exhaust blockage has improved.
At this time, the reference power is returned to the value before the exhaust blockage or the like.

[0008]

According to the first characteristic structure, even when the exhaust gas is blocked, the same amount of air blow as under the ideal condition can be maintained, so that the air-fuel ratio can be maintained at a predetermined value.

In the second characteristic configuration, when the condition such as exhaust blockage is improved, the reference power is returned to the value before the exhaust blockage occurs, so that the air-fuel ratio can be maintained at a predetermined value.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a water heater having a heat exchanger 1 for heating water, a burner 2 for heating the heat exchanger 1, and a fan 3 for supplying combustion air to the burner 2 are provided. It is provided. In the figure, W1 is a water supply passage for the heat exchanger 1, and W2 is a hot water supply passage W2. The fuel gas supply path G1 for the burner 2 is provided with two on-off valves 4 and 5 for connecting and disconnecting the fuel gas supply, and an electromagnetic gas amount adjusting valve 6 for adjusting the fuel gas supply. In the water supply passage W1, a water amount sensor S1 for detecting the amount of water supplied to the heat exchanger 1, and the heat exchanger 1
An incoming water temperature sensor S2 for detecting the incoming water temperature is interposed. A hot water outlet sensor S3 for detecting the hot water temperature of the heat exchanger 1 is provided in the hot water supply passage W2. In the figure, 7 is an igniter, and 8 is a frame rod for detecting whether or not the burner 2 is ignited. These are connected to the controller H, respectively.

A main remote controller R1 for commanding control information to the controller H and a bath remote controller R2 are provided. The main remote controller R1 is provided with an operation switch 21, a hot water supply temperature display 22, a hot water supply temperature setting device 23, and the like for instructing the start / stop of the operation. The bath remote control R2 is provided with an operation switch 31, a hot water supply temperature indicator 32, an additional heating switch 33, a hot water switch 34, and the like.

The configuration of the controller H will be added. As shown in FIG. 2, an input unit 41 for inputting command information and detection information of each sensor from the main remote controller R1 and the bath remote controller R2, and a combustion amount for obtaining the combustion amount Gp of the burner 2 based on the information from the input unit 41 Calculation unit 42, combustion amount Gp
Based on the target rotational speed Ns of the fan 3 and the reference current Is
, A fan setting unit 43 that controls the drive current If of the fan 3 so that the rotation speed of the fan 3 matches the target rotation speed Ns, and a rotation speed detection unit 45 that detects the rotation speed of the fan 3. A current detection unit 46 that detects the drive current If of the fan 3, a load detection unit 47 that detects the load of the fan 3 based on the deviation between the reference current Is and the drive current If,
Each of the adjustment valve drive units 48 that adjust the opening degree of the gas amount adjustment valve 6 is provided.

The operation of the controller H will be further described. The drive current If of the fan 3 is controlled so that the rotation speed of the fan 3 matches the target rotation speed Ns set based on the combustion amount Gp of the burner 2. The correspondence between the combustion amount Gp of the burner 2 and the target rotation speed Ns of the fan 3 is shown in Expression 1 (see FIG. 6).

[0014]

## EQU1 ## Ns = α × (a × Gp + b)

Here, α is a variable whose initial value is 1, a,
b is a constant. Target rotational speed Ns of fan 3 and fan 3
The corresponding relationship with the reference current Is of is shown in Equation 2 (see FIG. 7).

[0016]

(2) Is = β × (c × Ns + d)

Where β is a variable whose initial value is 1, c,
d is a constant. The correspondence relationship between them is the goal setting unit 43.
The setting is stored in. Target speed Ns and reference current Is
Is corrected based on the deviation between the reference current Is and the drive current If. When the deviation between the reference current Is and the drive current If becomes 5% or more of the reference current Is, the variable α is corrected 1.05 times and β is corrected 0.97 times. In this case, the reference current I
s becomes 1.02 times the original value. The solid lines in FIGS. 6 and 7 show the initial states of the target rotation speed Ns and the reference current Is, respectively. The dotted line shows how the target rotational speed Ns and the reference current Is change each time the variables α and β are corrected. on the other hand,
The deviation between the reference current Is and the drive current If is the reference current Is.
When the value becomes -5% or less, the variable α is corrected 0.95 times and β is corrected 1.03 times. In this case, the reference current Is becomes 0.98 times the original value. These corrections are performed based on a command from the load detection unit 47 to the target setting unit 43. That is, using the controller H, a rotation speed setting means 100 for setting a target rotation speed Ns of the fan 3, a reference setting means 101 for setting a reference current Is corresponding to the target rotation speed Ns, and a drive current of the fan 3. And a control means 102 for controlling the.

Next, the operation of the controller H will be described with reference to the flow charts shown in FIGS. First, it is determined whether or not hot water supply is necessary, and if hot water supply is not required, then it is determined whether or not hot water supply is currently being performed. If the hot water is not being supplied up to now, it returns as it is. If the hot water is being supplied up to the present, the control returns after executing the fire extinguishing process. When it is determined that the hot water supply is required, it is determined whether or not the ignition is being performed. Only when the ignition is not being performed, the ignition process for igniting the burner 2 is executed. Then, the combustion control of the burner 2 is executed. In the combustion control of the burner 2, first, the combustion amount Gp of the burner 2 is obtained. Next, the target rotation speed Ns and the reference current Is are obtained based on the equations 1 and 2. After that, the output is adjusted so that the obtained combustion amount Gp and the target rotation speed Nf match. Then, the drive current If at that time and the reference current Is are compared. When the deviation between the reference current Is and the drive current If is 5% or more of the reference current Is, the variable α is corrected 1.05 times and β is corrected 0.97 times. Further, the value of the counter n is incremented by 1. The initial value of the counter n is 0. The deviation between the reference current Is and the drive current If is
When the reference current Is is -5% or less, the variable α is corrected 0.95 times and β is corrected 1.03 times. Further, the value of the counter n is decremented by 1. If the deviation between the reference current Is and the drive current If is between 5% and −5% of the reference current Is, the values of the variables α and β and the counter n are not changed. Next, the value of the counter n is checked. If the counter n is larger than the predetermined value k or smaller than 0, abnormal processing is executed.

[Other Embodiment] In the above embodiment, the drive current If of the fan 3 is controlled so that the rotation speed of the fan 3 matches the target rotation speed Ns, but the drive voltage of the fan 3 is controlled. You may do it. In the above embodiment, the reference current Is is obtained from the correspondence relationship with the target rotation speed Ns.
The reference current Is may be directly obtained from the combustion amount Gp of the burner 2. That is, when the deviation between the reference current Is and the drive current If becomes 5% or more of the reference current Is, the reference current Is is increased by 1.02, while the deviation between the reference current Is and the drive current If is equal to the reference current Is. When it becomes -5% or less of Is, the reference current Is is corrected to 0.98 times.

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 configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 Overall configuration diagram

FIG. 2 is a block diagram of a control configuration.

FIG. 3 is a flowchart of control operation.

FIG. 4 is a flowchart of control operation.

FIG. 5 is a flowchart of control operation.

FIG. 6 is an explanatory diagram showing a relationship between a combustion amount and a target rotation speed.

FIG. 7 is an explanatory diagram showing a relationship between a target rotation speed and a reference current.

[Explanation of symbols]

 2 burner 3 fan 100 rotation speed setting means 101 reference setting means 102 control means If drive power Is reference power Ns target rotation speed

Claims (2)

(57) [Claims] 1. A fan (3) for supplying combustion air to a burner (2), and a rotation speed setting means (100) for setting a target rotation speed (Ns) of said fan (3) based on a combustion amount.
And a reference power (I) corresponding to the target rotation speed (Ns).
s) and a reference setting means (101) for controlling the driving power (If) of the fan (3) so that the rotation speed of the fan (3) matches the target rotation speed (Ns). (102) is provided, and when the deviation between the reference power (Is) and the drive power (If) exceeds a predetermined value, the rotation speed setting means (100) sets the drive power (If). A combustion fan control device configured to correct the target rotation speed (Ns) so as to match the reference power (Is), wherein the reference setting means (101) includes the reference power (Is).
The combustion fan control device is configured to correct the reference power (Is) to a value larger by a predetermined amount as the deviation between the drive power (If) and the drive power (If) exceeds a predetermined value. 2. The reference setting means (101) reduces the reference power (Is) by a predetermined amount as the deviation between the drive power (If) and the reference power (Is) exceeds a predetermined value. The combustion fan control device according to claim 1, which is configured to correct the value.