JP3018811B2 - Combustion control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion control device for an oil burning appliance.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, this type of combustion control device is energized to a heater 51 at the start of operation, and when a vaporizing cylinder 52 reaches a set temperature, the output from a vaporizing cylinder temperature control unit 53 is used as a burner. The fan 54 is driven, the fuel pump 55 is energized, the ignition device performs an ignition operation, and transitions to combustion. When the combustion is started, it is determined by the difference between the set temperature at that time and the room temperature while correcting the burner motor 57 or the fuel pump 55 so that the air-fuel ratio is set in advance by the oxygen sensor 56 attached to the exhaust path. It is configured to control combustion by the amount of combustion. When the temperature of the vaporizing cylinder drops below a predetermined temperature, the heater 51 is energized to increase the temperature of the vaporizing cylinder, and when the temperature of the vaporizing cylinder rises above the predetermined temperature, the power to the heater 51 is stopped so that the temperature becomes constant.

[0003]

However, in the above-mentioned conventional combustion control apparatus, the combustion performance is stable in any case of strong to weak in order to control the air-fuel ratio to be constant. Since the degree of heat recovery in the cylinder is greatly affected, the temperature of the vaporization cylinder may be easily changed. Therefore, even during normal combustion, there is a problem that the temperature may drop below the set temperature or the temperature of the vaporizing cylinder may extremely rise. If the temperature of the vaporizing cylinder drops below the setting, it is necessary to perform an operation to increase the temperature of the vaporizing cylinder by energizing the heater, and the cost of electricity increases, resulting in an extremely low economic efficiency. Conversely, if the temperature of the vaporizing cylinder rises too high, it will affect the heat resistance of the burner components and lead to a reduction in safety, and there is a problem of lack of economy and reliability.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to eliminate fluctuations in the temperature of a vaporizing cylinder to improve economic efficiency and reliability.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, the present invention provides a vaporizing cylinder for vaporizing and burning fuel.
A fuel pump for supplying fuel to the vaporizing cylinder and a burner fan for supplying combustion air to the vaporizing cylinder; a vaporizing cylinder temperature control unit for controlling the vaporizing cylinder temperature; A combustion control unit to be controlled, an oxygen sensor provided in an exhaust path of the combustion equipment, an oxygen concentration in the exhaust gas are measured, and the measurement result is compared with a preset oxygen concentration (air-fuel ratio target value). The correction amount is calculated so that the oxygen concentration in the gas becomes the air-fuel ratio target value, and the ventilation amount of the burner fan or the fuel supply amount of the fuel pump is corrected based on the calculation result, and the air-fuel ratio is maintained at a preset value. And an air-fuel ratio control unit for setting an air-fuel ratio target value in accordance with the state of the vaporization cylinder temperature.

[0006]

According to the present invention, when the temperature of the vaporizing cylinder is out of the set temperature range, the target value of the air-fuel ratio is changed and the combustion state is changed to adjust the temperature of the vaporizing cylinder so that the temperature falls within the set temperature range. I do. For example, when the combustion amount increases and the temperature of the vaporizing cylinder decreases, the air-fuel ratio is reduced to increase the temperature of the vaporizing cylinder. Conversely, when the combustion amount decreases and the vaporization cylinder temperature rises, the air-fuel ratio is increased to lower the vaporization cylinder temperature. in this way,
Provision of a more economical and safer combustion control device by automatically changing the combustion state according to the carburetor temperature and adjusting the carburetor temperature to suppress heater energization during combustion and abnormal rise in carburetor temperature can do.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. First, the configuration will be described with reference to FIG.
Denotes a motor, and 2 denotes a fan, which constitutes a burner fan for supplying combustion air. Reference numeral 3 denotes a vaporizing cylinder for vaporizing fuel and mixing it with combustion air, in which a heater 4 and a temperature detection sensor 8 are embedded. Reference numeral 5 denotes a fuel pump for supplying fuel into the vaporizing cylinder 3, reference numeral 6 denotes a heat exchanger for exchanging heat of the combustion gas, and reference numeral 7 denotes an exhaust path for discharging the heat-exchanged combustion gas.

Reference numeral 9 denotes an oxygen sensor which is attached to the exhaust passage 7 to measure the oxygen concentration in the combustion gas. Reference numeral 10 denotes a heater power supply of the oxygen sensor for heating a heater built in the oxygen sensor. Reference numeral 11 denotes a power supply for the sensor for generating a limiting current according to the oxygen concentration. Reference numeral 12 denotes an adjustment resistor, and the oxygen sensor 9
This is for adjusting the output. An amplifier 13 amplifies the output of the oxygen sensor 9 for input to the air-fuel ratio control unit.

An air-fuel ratio control unit 14 has a target value setting unit 14A in which the target value of the air-fuel ratio is set to a predetermined value in advance. Reference numeral 15 denotes a correction calculation unit that calculates a correction value by comparing the output of the oxygen sensor 9 with an air-fuel ratio target value. Reference numeral 16 denotes a burner motor rotation speed correction unit that determines an output value of the burner motor rotation speed based on the calculation result of the correction calculation unit 15.
Reference numeral 17 denotes a limiter which stops when the output value of the burner motor rotation speed is out of a predetermined range. 18
Is a burner motor drive circuit, 19 is a carburetor temperature setting section, 2
Reference numeral 0 denotes an air-fuel ratio target value correction calculating unit that compares the output of the carburetor temperature sensor 8 with the carburetor temperature set value to correct and calculate the target value of the air-fuel ratio. Reference numeral 21 denotes a limiter which limits the result of correcting the target value of the air-fuel ratio, and outputs an output for stopping the combustion when exceeding a predetermined range, that is, a limit at which abnormal combustion occurs.

Reference numeral 22 denotes a vaporizing cylinder temperature control unit, 23 denotes a pump drive circuit, and 24 denotes a combustion control unit. Although not described in detail, as in the conventional case, a room temperature signal from a room temperature detection unit and a set temperature signal from a temperature setting unit are used. The output is output to both the burner and the pump drive circuits so that the room temperature becomes the set temperature in comparison.

The operation of the combustion control device having the above configuration will be described with reference to the flowchart of FIG. First, a combustion operation is started according to a predetermined combustion sequence, and thereafter, combustion is performed under predetermined conditions until the combustion is stabilized. The target value correction of the air-fuel ratio due to the fluctuation of the carburetor temperature is not performed for a predetermined time until the combustion is stabilized. After a lapse of a predetermined time, the combustion control is performed based on the flowchart of FIG. 2 to adjust the carburetor cylinder temperature to a predetermined temperature range.

First, the temperature of the vaporizing cylinder is measured by the temperature detecting sensor 8, and is read in step 25 as temperature data.
Next, it is determined in step 26 whether the read temperature data falls within a preset temperature range. If the temperature of the vaporizing cylinder is within the set temperature range, the target value of the air-fuel ratio is set to a preset value. If the temperature of the vaporizing cylinder is out of the set temperature range, step 27 corresponds to the situation of the temperature of the vaporizing cylinder. In step 28, the target value is updated. In step 29, a new air-fuel ratio target value is set.

The operation of correcting the target value of the air-fuel ratio will be described in detail with reference to FIG. 3. First, a combustion amount of 4500 kcal / h
Assuming that the target value of the air-fuel ratio (m value) is 1.6
T1 (° C.) at the point. With this setting, the combustion amount is 4000k
cal / h, the vaporization cylinder temperature fluctuates to point D, and T
3 (° C). As a result, the temperature of the burner increases, which affects the heat resistance of the components and the vaporized state of the fuel, and may result in poor combustion. Therefore, when the temperature of the vaporizing cylinder rises above T1 (° C.), the air-fuel ratio (m value) is set to 1.6.
From 1.7 to 1.7, the combustion air amount is increased, the combustion state is shifted to the lift combustion side, the temperature of the carburetor cylinder is reduced, and the temperature is controlled to T1 (° C.) so as to reach the point E.

Next, when the combustion amount increases to 5500 kcal / h, the temperature of the carburetor fluctuates to the point B, and T2 (° C.)
Down to In general, the heater is energized to increase the temperature of the vaporizing cylinder by energizing the heater in order to prevent the combustion state from deteriorating when the temperature of the vaporizing cylinder falls below a predetermined temperature. And the economic efficiency drops dramatically. Therefore, when the temperature of the vaporization cylinder falls below T1 (° C.), the air-fuel (m value) is changed from 1.6 to 1.4, the amount of combustion air is reduced, and the combustion state is shifted to the red-fire combustion side. To raise the temperature of the vaporization cylinder to reach point C,
Control to 1 (° C).

As described above, a new target value of the air-fuel ratio is set according to the temperature of the carburetor cylinder, and the amount of combustion air is compared with the oxygen concentration data in the exhaust gas read by the oxygen sensor 9 attached to the exhaust path 7. Calculate the correction value of the burner motor rotation speed so that the value becomes an appropriate value, determine the correction amount, and output it to the burner motor drive circuit if the correction value does not exceed the limit value causing abnormal combustion, that is, if it is within the limiter range. Adjust burner motor speed. If it is out of the limiter range, stop the combustion.

By repeating the above operation, the combustion state is changed according to the temperature of the vaporizing cylinder, and control is performed to keep the vaporizing cylinder temperature constant without energizing the heater.

In the above-described embodiment, the case where the air flow rate of the burner motor is controlled when the air-fuel ratio target value is changed has been described.
Or, both may be used, and any configuration may be used as long as the object of the present invention is achieved.

[0018]

As described above, the combustion control apparatus according to the present invention can be used in addition to the air-fuel ratio control for adjusting the balance between the amount of combustion and the amount of combustion air so that the oxygen concentration in the exhaust gas is kept constant by the oxygen sensor. Since the combustion state is changed in accordance with the vaporization cylinder temperature by correcting the air-fuel ratio target value due to the fluctuation of the vaporization cylinder temperature and control is performed so as to keep the vaporization cylinder temperature constant, even if the combustion amount and the like fluctuate, the vaporization cylinder The temperature does not change, that is, the temperature of the vaporizing cylinder rises too high, and the heat resistance of the parts does not deteriorate. , Reliability and economy are greatly improved.

[Brief description of the drawings]

FIG. 1 is a block diagram of a combustion control device according to an embodiment of the present invention.

FIG. 2 is a flowchart of the apparatus.

FIG. 3 is a characteristic diagram showing an example of combustion control by the same device.

FIG. 4 is a block diagram showing a conventional combustion control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Burner motor 2 Burner fan 3 Vaporizer 5 Fuel pump 7 Exhaust path 9 Oxygen sensor 14 Air-fuel ratio controller 22 Vaporizer cylinder temperature controller 24 Combustion controller

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F23N 1/02 F23N 5/00 F23N 5/14 330

Claims (2)

(57) [Claims] 1. A vaporizing cylinder for vaporizing and burning fuel, a fuel pump for supplying fuel to the vaporizing cylinder, a burner fan for supplying combustion air to the vaporizing cylinder, and a vaporizing cylinder for controlling the temperature of the vaporizing cylinder. A temperature control unit, a fuel pump, a combustion control unit that controls a combustion amount by driving a burner fan, an oxygen sensor provided in an exhaust path of a combustion device, and an oxygen concentration in exhaust gas are measured. The set amount is compared with the set oxygen concentration (air-fuel ratio target value), and a correction amount is calculated so that the oxygen concentration in the exhaust gas becomes the air-fuel ratio target value. Based on the calculation result, the air flow of the burner fan or the fuel of the fuel pump is calculated. An air-fuel ratio control unit that corrects a supply amount, maintains an air-fuel ratio at a preset value, and sets an air-fuel ratio target value according to the state of the carburetor temperature. 2. The combustion control device according to claim 1, wherein the air-fuel ratio control unit has a limiter that outputs a combustion stop output when the correction amount for achieving the air-fuel ratio target value becomes abnormal combustion.