JP2604917B2 - Combustion equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic proportional valve for adjusting the amount of fuel supplied to a burner, a fan for supplying combustion air to the burner, and a target combustion for maintaining an air-fuel ratio at a predetermined value. Target setting means for setting a target opening of the electromagnetic proportional valve and a target rotation speed of the fan according to the amount; controlling the opening of the electromagnetic proportional valve to be the target opening; and And control means for controlling the rotation speed of the fan to be the target rotation speed.

[0002]

2. Description of the Related Art In the above-described combustion apparatus, when the target combustion amount changes, the opening degree of the electromagnetic proportional valve and the rotation number of the fan change to a new target opening degree and a target rotation number until they reach the target rotation number, respectively. In this case, it is necessary to maintain the air-fuel ratio at a predetermined value. By the way, since the time constant of the rotation speed of the fan in the transient response is relatively large, the time required to reach the target rotation speed becomes long. Therefore, in order to maintain the air-fuel ratio at a predetermined value, the rate of change of the target opening of the electromagnetic proportional valve is set to a relatively small value, and the target opening of the electromagnetic proportional valve is set to be extremely gentle.
It is necessary to gradually change in a state . Conventionally, the rate of change of the target opening and the rate of change of the target speed have been set to the same value so that the air-fuel ratio derived from the target opening and the target speed always becomes a predetermined value.

[0003]

The object of the invention is to be Solved However, the above-mentioned slave
With the conventional technology, the rate of change of the target opening of the solenoid proportional valve is sufficiently small.
If so, the deviation of the actual air-fuel ratio from the predetermined value
Not too large, but excessive until reaching the new target opening
Long response time to target combustion amount change command
Speed decreases. On the other hand, the target combustion amount change command
In order to improve the response speed with respect to
If the conversion ratio is increased, the actual air-fuel ratio in the transient state may deviate from the predetermined value, and there is a possibility that combustion may be defective. In other words, if the rate of change of the target opening and the rate of change of the target speed are the same value, the time constant of the fan speed is large, so the actual fan speed is Will be delayed. As a result, the actual air-fuel ratio in the transient state deviates from the predetermined value.
An object of the present invention is to solve the above-mentioned conventional disadvantages and to increase the response speed.
It is an object of the present invention to provide a combustion device that maintains the air-fuel ratio at a predetermined value even in a transient state and has a low risk of combustion failure.

[0004]

In order to achieve the above object, a characteristic configuration of the combustion apparatus according to the present invention is that the target setting means is configured such that when the target combustion amount changes, the target combustion amount is changed.
The target rotation speed and the target according to the target combustion amount of
Toward the opening, gradually increase the target rotation speed and the target opening.
And the rate of change of the target rotational speed is set to a value larger than the rate of change of the target opening.

[0005]

When the target combustion amount changes, the target rotation speed changes prior to the target opening. However, the delay of the actual fan rotation speed with respect to the target rotation speed is larger than the delay of the actual opening of the electromagnetic proportional valve with respect to the target opening. Therefore, by setting the change rate of the target rotation speed to a value larger than the change rate of the target opening, it is possible to cancel the delay of the actual rotation speed of the fan with respect to the opening of the electromagnetic proportional valve. That is, the target rotation
Assuming control to gradually change the number and target opening
While suppressing the deviation of the actual air-fuel ratio from the predetermined value, the response
When the rate of change of the target opening is increased to improve the speed
The air-fuel ratio can be maintained at the predetermined value even in the transient state in the case .

[0006]

According to the present invention, it is possible to obtain a combustion device which maintains the air-fuel ratio at a predetermined value even in a transient state and has a low possibility of combustion failure while improving the response speed .

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a water heater will be described with reference to the drawings. As shown in FIG. 1, a hot water supply device 1 connected to a hot water tap 4 via a hot water supply path W2 is provided, and a hot water supply device is configured. In the figure, W1 is a water supply channel.

[0008] The configuration of the water heater 1 will be described.
A burner 5, a heat exchanger 6 for water heating heated by the burner 5, two gas solenoid valves 7 and 8 for intermittently supplying fuel gas to the burner 5, and an electromagnetic proportional valve 9 for adjusting the fuel gas supply amount A fan 15 for supplying combustion air to the burner 5, a rotation sensor 16 for detecting the number of revolutions of the fan 15, an ignition plug 17 for igniting the burner 5, and a frame rod 18 for detecting ignition of the burner 5. Is decorated. The water supply passage W1 is provided with a water amount sensor 10 for detecting the amount of water passing through the heat exchanger 6 and an incoming water temperature sensor S1 for detecting the temperature of water supplied to the heat exchanger 6, and the water supply passage W2 is provided with a heat exchange passage. A hot water temperature sensor S2 for detecting the outlet hot water temperature of the vessel 6 is provided.

Next, a configuration for controlling hot water supply will be described. As shown in FIG. 1, a control device H using a microcomputer is provided. The control device H includes a water amount sensor 10, an incoming water temperature sensor S1, a hot water temperature sensor S2, a rotation sensor 16, and a frame rod 18. It is connected. Further, a remote controller 20 for instructing the operation information to the control device H is provided, and is connected to the control device H. The remote controller 20 is provided with an operation switch 21 for instructing the start and stop of the hot water supply operation, an operation lamp 22, a combustion lamp 23, and a hot water temperature adjustment button switch 24 for setting a hot water supply target temperature. The control device H is configured to control the gas solenoid valves 7, 8, the solenoid proportional valve 9, the fan 1 based on the information set and stored in advance and various input information.
5, and the operation of the spark plug 17 is controlled.

Electromagnetic proportional valve 9 when target combustion amount changes
The setting of the target opening degree and the target rotation speed of the fan 15 will be described with reference to FIG. Here, the target opening calculated from the same target combustion amount (reference target opening)
And the target rotation speed (reference target rotation speed) are treated as being the same value. For example, the target opening (temporary target opening) used for transient control when the target combustion amount changes and the reference target opening and the reference target rotation speed change from X1 to X2.
Is indicated by an alternate long and short dash line, and a target rotational speed (temporary target rotational speed) is indicated by a chain line. As is apparent from FIG.
The degree is gradually changed, and the provisional target opening is set to change by ΔV every predetermined time ΔT, and the provisional target rotation speed is set to change by ΔN every predetermined time ΔT. Here, ΔN is Δ
It is larger than V. That is, the rate of change of the target rotation speed when the target combustion amount changes is set to a value larger than the rate of change of the target opening. Then, the opening of the electromagnetic proportional valve 9 is controlled so as to be the provisional target opening, and the rotation speed of the fan 15 is controlled so as to be the provisional target rotation speed. That is, the target setting means 100 and the control means 101 are configured using the control device H.

Next, the operation of the control device H will be described with reference to the flowcharts of FIGS. First, it is determined whether or not the water amount is equal to or less than a set value based on a detection value of the water amount sensor 10, and if the water amount is equal to or less than the set value, the process returns. Here, if the hot water is being supplied until now, the process returns after executing the fire extinguishing process. If the water amount exceeds the set value, it is determined whether or not ignition is being performed, and if not, ignition processing for igniting the burner 5 is executed.
After ignition, a temperature control operation is performed to maintain the temperature set by the hot water temperature adjustment button switch 24. The temperature control operation will be described as follows. As described above, the target combustion amount of the burner 5 is calculated based on the hot water supply target temperature, the incoming water temperature, and the detected water amount, and the reference value of the electromagnetic proportional valve 9 is determined according to the target combustion amount. Target opening degree Vs and reference target rotation speed N of fan 15
s is set. Next, the reference target opening degree Vs and the reference target rotation number Ns are respectively compared with the provisional target opening degree Vo and the provisional target rotation number No at that time. Then, if there is a deviation, ΔV and ΔN are added to or subtracted from the provisional target opening degree Vo and the provisional target rotation speed No at predetermined time intervals ΔT, so that the provisional target opening degree Vo and the provisional target degree are reduced. The rotation speed No is gradually changed. Then, control is performed so that the opening of the electromagnetic proportional valve 9 becomes the tentative target opening Vo, and the rotation speed of the fan 15 becomes the tentative target rotation speed No.

Another Embodiment In the above embodiment, the case where the present invention is applied to a water heater is shown, but the present invention can also be applied to a combustion device such as a fan heater.
In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

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

FIG. 2 is a flowchart of a control operation;

FIG. 3 is a flowchart of a control operation.

FIG. 4 is an explanatory diagram of setting of a target opening and a target rotation speed.

[Explanation of symbols]

 5 Burner 9 Electromagnetic proportional valve 15 Fan 100 Target setting means 101 Control means

Claims (1)

(57) [Claims] An electromagnetic proportional valve (9) for adjusting a fuel supply amount to a burner (5), a fan (15) for supplying combustion air to the burner (5), and an air-fuel ratio maintained at a predetermined value. Target setting means (100) for setting a target opening of the electromagnetic proportional valve (9) and a target rotational speed of the fan (15) according to a target combustion amount, and the electromagnetic proportional valve (9). Control means (101) for controlling the opening of the fan (15) to the target opening and controlling the rotation speed of the fan (15) to the target rotation speed. The target setting means (100) is adapted to change the target combustion amount;
When the above, the above according to the target combustion amount after the change
Toward the target rotation speed and the target opening, the target rotation speed
And a combustion apparatus configured to gradually change the target opening and set the rate of change of the target rotation speed to a value larger than the rate of change of the target opening.