JPS6373015A - Combustion controller - Google Patents

Abstract

PURPOSE:To permit combustion effected by the optimum air-fuel ratio at all times, by a method wherein the title controller is provided with a temperature compensating means, regulating the supplying amount of fuel by a ratio in which the change ratio of the amount of work of a fan with respect to the change of a combustion air temperature is subtracted from the change ratio of the amount of air with respect to the change of the combustion air temperature. CONSTITUTION:A temperature compensating circuit 16 is provided with an air temperature sensor 17, detecting the temperature of combustion air induced into a fan 7, and inputs the control output (voltage signal) of an air-fuel ratio control circuit 15 while the same circuit 16 regulates the output of itself with a predetermined ratio with respect to the change of the combustion air temperature. According to this method, the fluctuation of the amount of air due to the change of the combustion air temperature and the fluctuation of the amount of work of a fan due to the same are compensated whereby combustion may be effected with the optimum air-fuel ratio at all times while the regulation of the output of combustion effected by the compensation of temperature may be coped with the fluctuation of loads in summer and winter, therefore, efficient combustion control may be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a combustion control device suitable for use in combustion equipment such as water heaters.

(B) Conventional Technology In recent years, combustion equipment such as water heaters have been designed to supply a constant fuel to the burner according to the load, combustion air from a blower, and a silent ratio adjusted.

In addition, in the combustion control device disclosed in Japanese Patent Application Laid-Open No. 60-69420, in order to compensate for fluctuations in air amount due to changes in combustion air temperature, Temperature compensation was performed by adjusting the fuel supply amount according to the ratio.

(c) Problems to be solved by the invention The above-mentioned combustion control device adjusts the fuel supply amount according to the combustion air temperature, but there is no consideration given to the amount of work of the blower due to changes in the air amount. It wasn't. Ding, that is,
If the fuel supply amount is temperature-compensated at a ratio corresponding to the change in air volume due to changes in air temperature, the amount of fuel supply will be reduced because the amount of work (rotation speed) of the blower changes due to changes in air temperature. The adjustment was excessive and combustion could not be performed at the optimum air-fuel ratio.

This invention was developed in view of the above-mentioned facts, and compensates for fluctuations in air volume and blower work due to changes in combustion air temperature, so that combustion can always be performed at the optimal air-fuel ratio. The purpose is to

Is there a way to solve the problem? Does this invention provide combustion air that can be filtered by the blower and the fuel appropriate to the load? : In the case where the air-fuel ratio is sub-adjusted and supplied to the burner trap, the fuel supply amount is calculated by subtracting the rate of change in the blower's work load in response to a change in combustion air temperature from the rate of change in air amount in response to a change in combustion air temperature. This configuration includes temperature compensation means for adjustment.

(e) Effect With this configuration, the amount of fuel supplied is adjusted at an appropriate ratio taking into account the amount of air with respect to changes in combustion air temperature and the rate of change in work of the blower.
C air-fuel ratio is always maintained optimally.

(f) Examples Examples of the present invention shown in the drawings will now be described in detail.

FIG. 1 shows a final embodiment of this invention applied to a combustion control device for an instant heating type water heater.

In the zH, 1 is a burner, 2 is a heat exchanger that is heated by the burner 1, 3 is inserted into the heat exchanger 2, and water from a water supply source (not shown) is heated by the heat exchanger 2. After that, a water circuit 4 for sending fuel oil to the usage part has an oil level regulator 5 and an oil feed pump 6, and a fuel supply pipe for sending fuel oil from an oil source (not shown) to the burner 1;
7 is a blower, 8 is equipped with a movable shutter 9, the blower 7 discharges combustion air Z, and the air supply pipe is regulated to a set amount and sent to the burner 1; 10 is an air supply pipe on the outlet side of the heat exchanger 2; A hot water temperature sensor 11 detects the hot water temperature in the water circuit 3, a remote control temperature setting device 12, and a CP T D (proportional/integral・Differential) control (PTD control circuit that emits the i signal, 1
3 is a damper motor that drives the movable shutter 9 in accordance with the PID control signal of the control circuit 12; 14 is a potentiometer that is driven by the damper motor 13 and generates a voltage signal corresponding to the control position signal of the damper motor 13;
Reference numeral 5 denotes an air-fuel ratio control circuit which calculates the fuel supply amount commensurate with the hot water supply load and the air supply amount to the burner 1 from the voltage signal of the potentiometer 14, and 16 determines the temperature of the combustion air sucked into the blower 7. It has an air temperature sensor 17 for detecting,
A temperature compensation circuit serves as a temperature compensation means which inputs the control output (1! pressure signal) of the air-fuel ratio control circuit 15 and adjusts its own output at a predetermined ratio in response to changes in combustion air temperature; 18 is a temperature compensation circuit; The oil feed pump 6 is controlled by PWM (pulse width modulation) according to the control output ('I! pressure signal) of the compensation circuit 16.
This is an oil pump control circuit that is driven by this method.

The temperature compensation circuit 16 has an internal configuration as shown in FIG. In FIG. 2, 19 is an input terminal to which the control output (L-) of the air-fuel ratio control circuit 15 is supplied, and 20 is an output terminal which supplies the control output (Vouv) to the oil feed pump control circuit 18. Resistor 21 between terminals 19 and 20 of n et al.
is connected, and a resistor 2 is connected between the output terminal 20 and the 7-seat 22.
3 and an air temperature sensor 17 consisting of a negative characteristic thermistor are connected in series. If vI and l of these resistors 21 and 23 and the air temperature sensor 17 are constant at 5V, the detected temperature of the air temperature sensor 17 becomes 2, as shown in FIG.
When the temperature is 0℃, voat is 4V and the detected temperature is 1
It is set so that Voσ〒 decreases (increases) at a rate of 3% every time it increases (decreases) by 0 degrees. This adjustment ratio (3%) is calculated from the rate of change in the amount of air (minus 4% per 10 degrees) with respect to the change in temperature of the combustion air detected by the air temperature sensor 17. (Minus 1 per 10 degrees
%).

According to this example, depending on the deviation between the hot water temperature in the water circuit 3 on the outlet side of the heat exchanger 2 and the temperature set by the temperature setting device 11,
, = the damper motor 13 according to the PiDffilJ control signal.
is driven. Then, the movable shutter 9 is driven by the °C damper motor 13, and the combustion air discharged from the air blower m7 is regulated to an appropriate amount by the movable shutter 9, and then supplied to the burner 1. A constant voltage signal is supplied from the potentiometer 14 to the air-fuel ratio control circuit 15 in response to the control position signal of the damper motor 13.
Since the 0 control output is supplied to the oil feed pump control circuit 18 via the temperature compensation circuit 16, the amount of fuel supplied to the burner 1 is adjusted to an appropriate amount commensurate with the hot water supply load and the amount of nitrogen spoon supplied to the burner 1. Sanro. Therefore, the burner 1 performs combustion commensurate with the hot water supply load, and the heated filtrate of the water circuit 3 is heated to near the set temperature when passing through the heat exchanger 27.

In parallel with the above-mentioned adjustment of the fuel supply amount based on the hot water supply load, the fuel supply amount is also adjusted based on the combustion air temperature. When the combustion air temperature rises above 20° C., the temperature compensation circuit 16 reduces its own output sound by 93% per 1 Odeg, and reduces the fuel supply amount. Conversely, when the combustion air temperature drops below 20°C, the temperature compensation circuit 16
Increases own output at a rate of 3% per 0 degrees and increases fuel supply amount. Therefore, even if the combustion air temperature changes, the total air volume and the amount of work of the blower 7 will change.
By compensating for IJ, the air-fuel ratio can always be optimized, and good combustion conditions can be maintained. Moreover, the combustion output is reduced in summer when the hot water supply load is small, and the combustion output is increased in summer when the hot water supply load is large, so that temperature compensation is possible that is suitable for the hot water supply load.

(G) Effects of the Invention Since the present invention is configured as described above, it compensates for fluctuations in the amount of air and the work of the blower due to changes in the combustion air temperature, and always performs combustion at the optimum air-fuel ratio. It is economical, and the combustion output can be adjusted to match load fluctuations in summer and winter by temperature compensation.
This makes it possible to achieve efficient combustion control.

[Brief explanation of the drawing]

@Figure 1 is an overall configuration diagram of a combustion control device according to an embodiment of the present invention, and Figure 2 is an FF of a temperature compensation circuit as temperature compensation means.
The three-part circuit diagram, FIG. 3, is an explanatory diagram of control characteristics of the temperature compensation circuit. 1...Burner, 7...Blower, 16...Temperature compensation circuit (temperature compensation means).

Claims (1)

[Claims] (1) In a combustion control device that adjusts the air-fuel ratio of fuel commensurate with the load and combustion air from a blower and supplies it to the burner, the rate of change in the amount of air with respect to the change in combustion air temperature is A combustion control device characterized by comprising temperature compensation means for adjusting the amount of fuel supplied at a rate that reduces the rate of change in the amount of work of a blower.