JPS59145429A - Combustion control device - Google Patents

Abstract

PURPOSE:To enable the gentle ignition according to the signals including a setting temperature, an amount of inflowing water and an inflowing water temperature, and realize a combustion control device having less-overshoot and excellent response characteristics by a method wherein a gentle ignition circuit of which gentle igniting function is varied according to signals from a temperature setting unit, an inflowing rate detector and an inflowing water temperature detector. CONSTITUTION:When an amount of water (m) inflowing into a heat exchanger 1 is detected with a flow rate detector 8, a main valve 9 is opened with a control circuit 6, an ignitor 11 is also operated. Simultaneously, an input (f) from a gentle ignition circuit J is selected in an input selecting circuit F, then a fan motor 5 is driven with the output (g). Subsequently, when a flame is detected with a flame detector 12, the gentle ignition is made only for designated time, the fan motor 5 is driven with an input (e) from a phase computing circuit E selected in the input selecting circuit F. The valve opening angle of a proportional valve 7 is varied proportional to the air pressure of the fan, then the gas burning is directed to designated condition. When the hot-water temperature rising of the heat exchanger 1 is detected with a thermistor 2, the deviation (c) between a hot-water temperature detecting signal (a) and a desired temperature signal (b) is obtained by a control circuit 6, then the designated control value (d) is calculated by a PID calculation D for said deviation (c).

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to combustion control, and in particular, a predetermined control amount is determined by PID calculation from the deviation between the outlet temperature and the target temperature, and the combustion state in the burner is determined by the outlet amount. Ii
The present invention will be used to improve combustion control devices such as those used in water heaters that operate to maintain the temperature at about 1 Rai degree.

BACKGROUND OF THE INVENTION FIG. 1 is a diagram showing the sequence of soaking control operation in a conventional combustion control device, and FIGS. 2A and 2B are diagrams showing the combustion amount and hot water output of the conventional combustion control device and an embodiment of the present invention. FIG. 3 is a waveform diagram showing the relationship with temperature. First, an operation sequence in a conventional combustion control system will be described with reference to FIG. When the amount of water flowing into the heat exchanger is detected by a water amount detector (not shown), the original pulp (not shown) is opened and an igniter (not shown) is activated, and at the same time, the input selection circuit receives a fixed input f from the slow ignition circuit. Select and
The fan motor is driven by the output Ω. As a result, after the gas is detected and a flame is detected by a flame detector (not shown), the slow ignition operation is continued for a predetermined period of time. After the slow ignition operation is completed, the input selection circuit selects the input e from the phase calculation circuit to drive the fan motor. Then, the opening degree of the proportional valve changes in proportion to the air pressure, and the gas combustion in the burner moves toward a predetermined state.

When the increase in temperature of the heat exchanger is detected by the thermistor, 318! A deviation C between the detection signal a and the target temperature signal S is determined, and a predetermined control amount d is created by performing a PID calculation on this deviation C. Next, based on this control amount d, the phase angle for driving the fan motor is calculated and determined, and outputted via the input selection circuit. When a trigger signal 9 is thereby outputted to the switching element that turns on and off the drive current of the fan motor, the fan motor reaches a predetermined rotation speed. As a result, the predetermined air pressure is transmitted to the proportional valve, the valve opening becomes the predetermined opening, the amount of gas supplied to the burner is optimized, and the output temperature becomes the set temperature. controlled.

By the way, as is well known, the set temperature of a water heater ranges from 30°C to 80°C, and the water temperature ranges from 0°C to 30°C.
It has a width of about ℃, and the inflow water amount is 4 to 16 fl/win
It has a width of f & degrees. For this purpose, the following conditions (in particular,
(When the set temperature is low and the inlet water temperature is high and the inflow water amount is small)
In this case, as shown by dotted lines a and b in FIG. 2A, the target temperature may be exceeded only by the amount of gas during slow ignition and the time of slow ignition. Finally, the target a! is achieved through feedback control. Although the temperature can be obtained, it is extremely inconvenient and inconvenient for users who want to quickly obtain the desired temperature. Therefore, effective measures that can improve the above-mentioned drawbacks have been desired.

Purpose of the Invention Therefore, the main purpose of the present invention is to improve response characteristics so that overshoot can be reduced under any conditions such as set temperature, inlet water temperature, inlet water amount, etc., and that the target temperature can be obtained quickly. The purpose is to provide a combustion engine.

Structure and Effects of the Invention The present invention replaces the conventional circuit that performs slow ignition with a fixed value, and uses a slow ignition circuit that changes the slow ignition ability according to signals from an m degree setting device, an inlet water temperature sensor, and a flow rate detector. Since it is configured with an ignition circuit, the set temperature.

It becomes possible to perform slow ignition according to the conditions of the inflowing water layer and the inflowing water humidity, and as a result, it becomes possible to realize a combustion control device with excellent response characteristics and less overshoot.

Description of examples Embodiments of the present invention will be described below based on the drawings.

FIG. 3 is a block diagram showing the basic configuration of a water heater to which the present invention is applied. This water heater shown in FIG. A control circuit 6 that controls the rotation speed of the furn motor 5 based on the deviation between the hot water temperature detection signal and the target temperature setting signal of the target temperature setting device 3;
Basically, a proportional valve 7 is provided in the gas supply path to the burner 4 and operates so that the valve opening changes according to the air pressure blown by the fan motor 5 so that the pressure of the gas supplied to the burner 4 is proportional to the air pressure. has.

A flow rate detector 8 and an inlet water temperature detector 14 are provided at the inlet of the water leading to the heat exchanger 1 to detect the amount of water passing through the heat exchanger 1 and the temperature of the inlet water, and to input these to the control circuit 6. Further, a gas supply path leading to the proportional valve 7 is provided with a source valve 9 that turns on and off the supply of gas and a gas governor 10. An igniter 11 that generates ignition sparks in relation to the burner 4, a flame detector 12 that detects whether or not the ignition is normally ignited by the ignition operation, and a wind pressure switch that confirms the operating state of the fan motor 5. 13 are provided.

FIG. 4 is a sequence diagram of an embodiment of the present invention. Next, the operation will be explained with reference to FIGS. 2 and 3 together with the sequence diagram in FIG. 4. First, when the flow rate detector 8 detects the amount of water flowing into the heat exchanger 1, the control circuit 6 opens the main valve 9 and operates the igniter 11. At the same time, the input selection circuit selects the input f from the slow ignition circuit and drives the fan motor 5 with its output O. Note that the input f to the input selection circuit at this time calculates the slow ignition amount based on the set temperature signal, the incoming water concentration detection signal, and the flow rate detection signal i, and transmits the calculation result J to the limiting circuit. do. and,
If the calculation result j is within the slow ignition gas amount variable range, the calculation result J is used as the input f. Further, if the calculation result J is larger or smaller than the m-point large gas amount variable range, the upper limit or lower limit of the slow ignition gas amount variable range is set as input t.

Note that the * calculation at this time is to calculate the M ignition capacity according to the method shown below.

Inlet water temperature is TI ('C), set temperature is TC ('C)
.

If the flow rate of water is Q (vis/min) and the ignition capacity is G (number), then it becomes G-(Tc-TI)XQ/25 (number). Here, "No.", which is the unit of slow ignition ability G, is an expression unique to Onjoshiki. ).

Next, when the flame detector 12 detects a flame, slow ignition is performed for a predetermined period of time, and then the input selection circuit selects the input e from the phase calculation circuit to drive the fan motor 5. The valve R degree of the proportional valve 7 changes in proportion to the air pressure, and the burner 4
The gas combustion at is directed towards a predetermined state. Next, when the thermistor 2 detects an increase in the humidity at the outlet of the heat exchanger 1, the control circuit 6 calculates the deviation C between the hot water temperature detection signal a and the target temperature signal S, and performs a PID calculation on this deviation C. Do the prescribed control! Create ld. And this control 1f
id k: Calculate and determine the phase angle to drive the fan motor 5 based on. The result of this operation is outputted via the input selection circuit, and the fan motor 5 reaches a predetermined rotation speed. As a result, a predetermined amount of air is transmitted to the proportional valve 7, the valve opening becomes the predetermined opening, the amount of gas supplied to the burner 4 becomes optimal, and the temperature of the output 111 becomes as close as possible to the set temperature. controlled.

The above-described operations are repeated to maintain the hot water humidity at the set temperature, and the burner 4 continues to burn at a predetermined amount of gas. If there is a change in the set temperature or specific weight, the change in the output temperature is fed back, and the output temperature is corrected by the above-mentioned control operation. next,
The slow ignition operation will be explained based on FIG. 2A and FIG. 2B. Slow ignition is generally about 1/1 of the maximum combustion capacity.
Selected as 2nd grade. This was chosen under the conditions that it is easy to ignite and produces a low 'a* sound. The upper limit of the variable range of slow ignition gas amount shown in Figure 2A and Figure 2B is:
The upper limit value is the gas amount with a small ignition sound, and the lower limit value is the lower limit value of the ability in terms of ease of ignition. Therefore, the second
Figures A and 2B show that the slow ignition gas amount changes depending on the required gas amount, and the variable range is limited to the slow ignition gas amount variable range. In this way, as is clear from the waveforms d to h shown by the solid lines in Figures 2A and 2B, the slow ignition ability is changed based on the signals from the temperature setter, inlet water temperature detector, and flow rate detector. Therefore, combustion control with good response characteristics and little overshoot can be performed under any conditions.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an operation sequence of a conventional combustion control device. FIG. 2A and FIG. 2B are waveform diagrams showing the relationship between the combustion amount and the hot water discharge m degree in a conventional combustion control device and an embodiment of the present invention. FIG. 3 is a basic configuration diagram of a water heater to which an embodiment of the present invention is applied. FIG. 4 is a sequence diagram of an embodiment of the present invention. In the figure, 1 is a heat exchanger, 2 is a hot water temperature detector, 3 is a temperature setting device, 4 is a burner, 5 is a fan motor, 6 is a control circuit, 7 is a proportional valve, 8 is a flow rate detector, and 9 is an original valve. , 10
11 is a gas governor, 11 is an igniter, 12 is a flame detector, 13 is a wind pressure switch, and 14 is an inlet water temperature detector. 10-

Claims (2)

[Claims] (1) A temperature detector that detects the hot water temperature of the heat exchanger;
In the combustion control device, the combustion control device includes a temperature setting device that sets the degree of collapse, a proportional control valve that supplies fuel to the burner, and a control circuit that controls the opening degree of the proportional control valve. an inlet water temperature detector that detects the amount of water flowing into the heat exchanger; a flow rate detector that detects the amount of water flowing into the heat exchanger; and output signals of the temperature setting device, the water inlet temperature detector, and the flow rate detector, respectively. 1. A combustion control device comprising slow ignition means for changing the opening degree of the proportional control valve at the time of ignition according to the ignition. (2) The combustion control device according to claim 1, wherein the slow ignition means includes a control means that changes only within a maximum and minimum range of an allowable slow ignition capability range of the water heater.