JPH01239319A - Combustion device - Google Patents

Abstract

PURPOSE:To reduce the waste of electric power caused by a size of load and a differential temperature of an ignition heater and an evaporating heater, by regulating power supply to the ignition heater corresponding to the temperature of the evaporation heater so that the ignition heater reaches a specified ignition temperature when the evaporated fuel gas reaches the ignition heater. CONSTITUTION:In the case the temperature of an evaporation heater R0 is lower than R1 when an operation switch is turned ON, simultaneously power supply to the evaporation heater begins and its temperature begins to rise. When the temperature of the evaporation heater reaches R1, power supply to the ignition heater begins, and when the temperature of the evaporation heater reaches R2, a magnetic pump is put into operation to feed fuel gas to a burner, so that ignition takes place. The evaporation heater having a rather large capacity is started first and then power is supplied to the ignition heater after the evaporation heater is pre-heated up to a temperature equivalent to R1 so as to synchronize the time at which the evaporation heater reaches a temperature sufficient for evaporating liquid fuel with the time at which the ignition heater reaches a desired ignition temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a combustion device that vaporizes and burns liquid fuel, such as a household stove, a central heating boiler, or a range.

[Prior Art] There are two commonly known combustion devices of this type: one uses a high-pressure discharge (igniter) as the ignition means, and the other uses an ignition heater to make it red-hot to ignite. There were different methods.

The former method of ignition using high-pressure discharge has the drawbacks of causing a sense of anxiety due to the sound generated during discharge, and malfunctioning of the built-in control microcomputer due to noise.

On the other hand, as for the method of igniting with an ignition heater, there is one that has been generally known from the past, for example, the one described in Japanese Utility Model Application Publication No. 125853/1983, in which the vaporization heater first burns liquid fuel. The fuel gas is vaporized and the vaporized fuel gas is supplied to the bath, and the fuel gas is ignited by a red-hot ignition heater, so there is no inconvenience caused by the sound and noise associated with the high-pressure discharge mentioned above. There is an advantage.

[Problem to be Solved by the Invention 8] However, in this kind of conventional combustion device using an ignition heater, since the ignition heater and the vaporization heater were started to be energized at the same time, depending on the conditions, the above-mentioned There were cases where the energization time of one of the heaters was longer than necessary. In other words, in conventional devices, the load on the vaporization heater is generally higher than on the ignition heater, and if both heaters were turned on at the same time, the ignition heater would have already reached the predetermined ignition temperature. Even though the vaporization heater has reached the predetermined vaporization temperature, there may be a situation where the vaporization heater has not yet reached the predetermined vaporization temperature, and the ignition heater continues to be energized in vain until the vaporization heater reaches the predetermined vaporization temperature. There was an inconvenience in having to do so. In addition, there are cases where the vaporization heater has warmed up to a certain extent, such as when the combustion device is temporarily stopped for a short time and then restarted, and even in such cases, conventionally Since the energization of the evaporation heater and the evaporation heater was uniformly started and controlled at the same time, the energization could not be optimally controlled according to the temperature of the evaporation heater, resulting in unnecessary energization. .

That is, in the past, there was a drawback that power consumption was wasted due to the difference in load between the ignition heater and the vaporization heater, the temperature difference, and the like.

In view of the above-mentioned circumstances, the present invention reduces wasted power consumption caused by the size of the load or temperature difference between the ignition heater and the vaporization heater by controlling the energization taking into account the temperature of the vaporization heater. The purpose is to

[Means for Solving the Problems] A combustion device according to the present invention includes a vaporizing heater that is heated by being energized and uses the heat to vaporize liquid fuel, and a temperature sensor that detects the temperature of the vaporizing heater. a fuel supply means for supplying liquid fuel to be vaporized by the vaporization heater; and an ignition heater that is heated by being energized and ignites the fuel gas vaporized by the vaporization heater. , a burner that burns the fuel gas ignited by the ignition heater;
In response to the detection output of the temperature detection means, the ignition heater is configured to adjust the ignition heater to a predetermined ignition temperature when the fuel gas vaporized by the vaporization heater reaches the ignition heater. and energization control means for controlling energization of the device.

[Operation] The fuel gas vaporized by the vaporization heater is ignited by the ignition heater and burned in the burner section. Further, the temperature of the vaporization heater is detected by the temperature detection means. Then, by the function of the energization control means, the temperature of the vaporization heater is taken into consideration, and the ignition heater is set to a predetermined ignition temperature when the fuel gas vaporized by the vaporization heater reaches the ignition heater. The energization of the ignition heater is controlled, and detailed energization control is performed in consideration of the temperature of the vaporization heater.

[Embodiments of the invention] Next, embodiments of the present invention will be described based on the drawings.

FIG. 1 is a schematic explanatory diagram of the main parts of a household stove which is an example of a combustion device according to the present invention.

Oil such as kerosene, which is an example of liquid fuel, is stored in an oil tank 21, and the oil in this oil tank 21 is configured to be supplied in appropriate amounts into an oil pan 2 provided below. . The oil in this oil pan 2 is supplied into the blower 3 by the electromagnetic pump 1. A vaporizing heater 4 made of a ceramic heater is provided inside the vaporizer 3, and is configured to be heated by being energized to vaporize the supplied oil. The vaporized fuel vaporized by the vaporizer 3 equipped with the vaporization heater 4 is ejected from the nozzle 7 and supplied into the burner 8 . Note that this nozzle 7 is controlled to open and close by a solenoid valve 6.

The fuel gas supplied into the burner 8 is ignited and burned by an ignition heater 10 made of a ceramic heater.

A net 9 is provided above the burner 8.

Further, a thermistor 5 for detecting the temperature of the vaporization heater 4 is provided, and this thermistor 5 constitutes a temperature detection means for detecting the temperature of the vaporization heater 4. Further, the electromagnetic pump 1 constitutes a fuel supply means for supplying liquid fuel so that it is vaporized by the vaporization heater 4. FIG. 2 is an enlarged perspective view of essential parts showing the ignition heater and its peripheral equipment.

The ignition heater 10 is provided above the burner 8,
It is integrally formed with the frame rod 12 by an insulator 11. This flame rod 12 is for detecting the occurrence of electrical resistance due to ions generated between the flame rod 12 and the burner 8 during combustion of the fuel gas, and is used to ensure that the fuel gas is ignited as described later. This is to determine whether or not the

FIG. 3 is a block diagram showing a control circuit for controlling the combustion device.

The microcomputer 13, which is an example of the energization control means, is composed of, for example, several chips of LSI, and includes an MP that can execute control operations according to a predetermined procedure.
It includes a ROM 44 that stores operating program data for the MPU 40, and a RAM 42 that can write and read necessary data.

Furthermore, the microcomputer 13 includes an input circuit 28 that receives input signals and provides input data to the MPU 40;
An output circuit 30 that receives output data from the PU 40 and outputs it to the outside; a power-on reset circuit 32 that provides a reset pulse to the MPU 40 when the power is turned on; a clock generation circuit 34 that provides a clock signal to the MPU 40; It includes a pulse frequency divider circuit (interrupt pulse generation circuit) 36 that divides the frequency of a clock signal and periodically supplies an interrupt pulse to the MPU 40, and an address decode circuit 38 that decodes address data from the MPU 40.

The MPU 40 can execute the operation of the interrupt control routine in response to interrupt pulses periodically given from the pulse frequency dividing circuit 36. In addition, the address decoding circuit 3
8 decodes the address data from the MPU 40, and R
OM44. RAM42, input circuit 28. A chip select signal is provided to each output circuit 30. In this embodiment, the ROM 44 is capable of rewriting its contents, that is, when the need arises, the MPU 4 stored therein can be rewritten.
A programmable ROM may be used so that the program data for 0 can be changed. and,
The MPU 40 provides control signals to various devices in accordance with program data stored in the ROM 44 and in response to input of each control signal described below.

As an input signal given to the microcomputer 13, first, information regarding the temperature of the vaporization heater by the thermistor 5 is input. Further, an electrical resistance signal from the frame rod 12 is input.

The microcomputer 13 then provides control signals to the following circuits and devices. First, a control signal for driving the ignition heater is given to the ignition heater 10 via the ignition heater drive circuit 20, which is an example of an ignition heater drive means. A control signal for driving the vaporizing heater 4 is given to the vaporizing heater 4 via the vaporizing heater driving circuit 22, which is an example of vaporizing heater driving means. A control signal for driving the electromagnetic pump is given to the electromagnetic pump 1 via an electromagnetic pump driving circuit 24, which is an example of an electromagnetic pump driving means. A control signal for driving the solenoid valve for opening and closing the carburetor nozzle is given to the solenoid valve for opening and closing the carburetor nozzle 6 via the solenoid valve drive circuit 26 for driving the solenoid valve for opening and closing the carburetor nozzle, which is an example of a solenoid valve driving means for opening and closing the carburetor nozzle. . In addition,
A predetermined direct current is supplied to each circuit of the above configuration from a power supply circuit (not shown).

FIG. 4 is a flowchart for explaining the operation of the control circuit of FIG. 3.

Next, the specific operation of this combustion apparatus will be explained with reference to FIGS. 1 to 4.

First, in step S1, it is determined whether or not the operation switch is turned on, and the process waits until the operation switch is turned on. When the operation switch is turned on, a YES determination is made in step S1, and the process proceeds to step S2, where it is determined whether the temperature measured by the thermistor is equal to or higher than R3.

At the start of normal operation, the vaporizing heater 4 is not warmed up at all, so the temperature measured by the thermistor is below R7, and a negative determination is made in step S2, and the process proceeds to step S3. In step S3, control is performed to turn on the vaporization heater, and the vaporization heater is energized and heated. Next, the process proceeds to step S4, where it is determined whether or not the temperature measured by the thermistor has reached R7. If it is determined that the temperature has not yet reached R1, the process returns to step S3 and the process of turning on the vaporization heater is performed. Continued. When the vaporization heater reaches a certain temperature and the temperature measured by the thermistor reaches R3, a YES determination is made in step S4 and the process proceeds to step S5. In step S5,
A process is performed in which the ignition heater is turned on and the vaporization heater continues to be turned on.

Next, the process proceeds to step S6, where the temperature measured by the thermistor is set to R2.
A determination is made as to whether or not R2 has been reached, and if R2 has not yet been reached, a NO determination is made in step S6, and the process returns to step S5 to continue the processing in step S5. This R2 is a higher value than R1 shown in step S4. When the temperature of the energized vaporization heater rises to a predetermined value and the temperature measured by the thermistor reaches R2, a YES determination is made in step S6 and the process proceeds to step S7, where the electromagnetic pump 1 is turned on and the nozzle is turned on. 7 (see FIG. 1) to supply fuel gas into the burner and to set the timer 2. Next, the process proceeds to step S8, where the fuel gas is ignited by the ignition heater, and the process proceeds to step S9, where it is determined whether the resistance of the flame rod has reached the flame level set value S. This frame level setting value S.

is the resistance value of the flame rod when ignition is ensured and there is no need to continue ignition,
If the ignition is still insufficient, the resistance of the flame rod becomes a value equal to or less than S, so a negative determination is made in step S9 and the process returns to step S8 to continue ignition. Then, the ignition is performed reliably and the resistance of the flame rod is S.

If this has been reached, a YES determination is made in step S9, and the process proceeds to step S10, where the ignition heater is controlled to be turned off.

Next, the process advances to step S11, and the set time T of timer 2
A determination is made as to whether T2 has elapsed or not, and the process waits until T2 has elapsed. Then, if T2 has elapsed, step S12
The process proceeds to step 2, where it is determined whether the resistance of the frame rod has reached the frame level set value S2. This S2 is a value that serves as a standard for determining whether or not combustion is being performed reliably and well by the burner after ignition is performed by the ignition heater. This is the resistance value of the frame rod. If combustion by the burner is not performed reliably and well even though time T2 has elapsed after ignition was started, step S is performed.
12, a NO determination is made, and the process proceeds to step S15, where the operation is controlled to stop. On the other hand, if the post-ignition time T2 has elapsed and the burner is performing combustion reliably and well, the resistance of the flame rod has reached 82, so a YES determination is made in step 812, and step Proceed to 313. In step 313, the vaporizing heater is controlled at a temperature corresponding to R8, and combustion is continued.The process then proceeds to step S14, where it is determined whether or not the operation switch has been turned off.
If the FF is not operated, return to step S1B,
The process of step S13 is continued. If the operator turns the operation switch OFF, a YES determination is made in step S14, and the process proceeds to step S15, where the operation is stopped.

Next, a case will be described in which the temperature of the vaporizing heater at the time when the operation switch is turned on is equal to or higher than R4.

In this case, since the temperature measured by the thermistor is equal to or higher than R4, a YES determination is made in step $2 and the process proceeds to step S16. In step S16, the ignition heater is turned on to start energizing the ignition heater, and timer 1 is set. Next, proceed to step S], 7, where the temperature measured by the thermistor reaches R3.
A judgment is made as to whether or not this is the case. This R1 is a value corresponding to the optimum temperature during operation of the vaporizing heater, and is a larger value than the above-mentioned R2. If the temperature of the vaporization heater is below this optimum temperature R3, the temperature of N is reduced in step S17.
After the determination of o is made, the process proceeds to step 818, where the vaporization heater is turned on to start energization, and the process proceeds to step S19. On the other hand, if the temperature of the vaporization heater is equal to or higher than the desired optimum temperature, the temperature determined by the thermistor is equal to or higher than R3, so a determination of YES is made in step S17, and the vaporization heater is not turned on and step S19 is made. Proceed to.

In step S19, it is determined whether or not the set time T of timer 1 has elapsed, and if it is determined that it has not elapsed yet, a small Do loop is formed in which the process returns to step S16. Then, this Do small loop is repeated until the set time T has elapsed, and each process from step S16 to step S18 is continued, and when the set time T has elapsed, a YES determination is made in step S19. The process then proceeds to step S6.

Next, the timing of energization of the vaporization heater and the ignition heater, which are controlled to be energized by flowchart 1 shown in FIG. 4, will be explained based on FIGS. 5A to 5D.

FIG. 5A shows a case where the temperature RO of the vaporizing heater at the time when the operation switch is turned on is a value equal to or lower than R4. In this case, energization of the vaporization heater is started at the same time as the operation switch is turned on, and the vaporization heater is warmed over time and its temperature increases. Then, when the vaporization heater reaches a temperature corresponding to R4, energization of the ignition heater is started. Next, when the vaporization heater reaches a temperature corresponding to R2, the electromagnetic pump is turned on.
When operated, fuel gas is supplied to the burner and ignition is performed by the ignition heater. By controlling the energization timing of both heaters in this way, the evaporation heater with a relatively large load starts energizing first, and after it has been warmed up to a temperature corresponding to R1, the ignition heater starts energizing. Control is performed so that the point in time when the vaporization heater reaches a temperature R2 at which the liquid fuel can be vaporized and the point in time when the ignition heater reaches a desired ignition temperature are made to coincide with each other.

Figures 5B and 5C show that the temperature RO of the vaporizing heater at the time when the operation switch is turned on is R5 and R.
The case where the value is between 2 and 2 is shown.

In this case, both the vaporization heater and the ignition heater are energized when the operation switch is turned on.

Then, a time period T elapses from the time when the vaporization heater is energized, and the temperature of the vaporization heater at that time point becomes R.
If it is 2 or more, as shown in Figure 5B,
Ignition is performed by the ignition heater by turning on the electromagnetic horn.

On the other hand, if the temperature of the vaporizing heater has not reached R2 at the time the time T has elapsed, as shown in FIG. 5C,
Wait until the temperature of the vaporization heater reaches a value corresponding to R2, and when it reaches R2, the electromagnetic pump is turned on for the first time, and ignition is performed by the ignition heater.

FIG. 5D shows a case where the temperature of the vaporizing heater at the time when the operation switch is turned on is equal to or higher than R3. In this case, when the operation switch is turned on, energization of only the ignition heater is started, but energization of the vaporization heater is not started. Therefore, the temperature of the vaporizing heater gradually decreases as shown in the figure, and when it reaches R2, the energization is controlled so that the temperature remains constant at R8. On the other hand, the ignition heater reaches the desired ignition temperature when a time T has elapsed since the ignition heater was turned on, and at that point the electromagnetic pump is turned on and ignited.

In this embodiment, as shown in steps S16 to S18 in FIG.
The energization of both the ignition heater and the vaporization heater will start at the same time, but in this case, since the vaporization heater is already warmed to a temperature equal to or higher than R7, the vaporization heater In particular, both heaters in this example are made of ceramic heaters and exhibit large resistance at high temperatures, so even if both heaters start energizing at the same time, the resulting inrush current will not be large. Therefore, there is no risk that the inrush current will become too large. Note that in order to avoid starting energization of the ignition heater and the vaporization heater at the same time, step S16 and step 81 shown in FIG.
Control may be performed so that a time lag is set between the start of energization of the ignition heater and the start of energization of the vaporization heater by inserting a step to allow some time to pass between 8 and 8.

In this example, a household stove was used as an example.
The present invention is not limited to this, and includes various devices such as central heating boilers and ranges, and in short, any combustion device that vaporizes and burns liquid fuel is included.

Furthermore, in this embodiment, in response to the detection output of the temperature detection means, the ignition heater is set to a predetermined ignition temperature when the fuel gas vaporized by the vaporization heater reaches the ignition heater. As the energization control means for controlling the energization of the ignition heater, the energization control means controls the energization start timing of the ignition heater, but the present invention is not limited thereto. By controlling the distribution ratio of the electric power supplied to both heaters after that, the point in time when the vaporization heater reaches the temperature at which it can vaporize and the point in time when the ignition heater reaches the predetermined ignition temperature are made to match. It may also be controlled in this manner. Furthermore, such a method of controlling the power distribution ratio may be combined with the method of controlling the energization start timing shown in the above embodiment.

[Effects of the Invention] The present invention having the above-mentioned configuration allows fine energization control to be performed in consideration of the temperature of the vaporization heater, and eliminates the problem caused by the difference in load size or temperature difference between the ignition heater and the vaporization heater. The waste of power consumption can be reduced as much as possible, and a combustion device with low power consumption can be provided.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of essential parts showing an example of a combustion apparatus according to the present invention. FIG. 2 is an enlarged perspective view showing the ignition heater and its peripheral equipment. FIG. 3 is a block diagram showing a control circuit for controlling the combustion device according to the present invention. FIG. 4 is a flowchart for explaining the operation of the control circuit shown in FIG. 3. FIGS. 5A to 5D are diagrams showing graphs for explaining timings for starting energization of the vaporization heater and the ignition heater. In the figure, 4 is a vaporizing heater, 1 is an electromagnetic pump which is an example of fuel supply means, 10 is an ignition heater, 5 is a thermistor which is an example of temperature detection means, and 13 is a microcomputer which is an example of energization control means. be. Figure 1 2 N-~ Rod SD diagram

Claims (1)

[Scope of Claims] A vaporizing heater for heating liquid fuel by being energized and vaporizing the liquid fuel using the heat; temperature detection means for detecting the temperature of the vaporizing heater; and a liquid fuel that is vaporized by the vaporizing heater. a fuel supply means for supplying liquid fuel; an ignition heater for igniting fuel gas heated by being energized and vaporized by the vaporization heater; and a fuel gas ignited by the ignition heater; a burner that combusts a burner; and in response to a detection output of the temperature detection means, the ignition heater has a predetermined ignition temperature when the fuel gas vaporized by the vaporization heater reaches the ignition heater. and energization control means for controlling energization of the ignition heater.