JPH10170069A - Combustion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an accurate detected value to be measured even if a sensing means such as a CO sensor is replaced by a method wherein at least one of a control means and a sensing means has discrimination data to be discriminated from the other and the other means is provided with a discriminating means for discriminating the discriminating data. SOLUTION: An output value of a CO sensor 40 when no combustion is carried out is applied as a zero point value and stored in a memory 83 of a main body substrate 80. Then, this zero point value is measured at a suitable time such as a turning-on of a power supply for a combustion device and after elapsing of a specified period of time upon completion of combustion. In the case that the measured value is different from the zero point value, a zero point correction is carried out. With such an arrangement as above, it is possible to attain an accurate CO concentration by calculating a difference between an output value from the CO sensor 40 during combustion and this corrected zero point value under a control of a CPU 82 at a main board 80. Accordingly, it is possible to accommodate for an aging variation of sensitivity at the CO sensor 40 and to attain an accurate CO concentration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion apparatus such as a water heater or a bath kettle, and more particularly, to a carbon monoxide gas sensor (hereinafter referred to as a CO sensor) for detecting a concentration of carbon monoxide gas at a predetermined concentration or higher. The present invention relates to safety detection means in a combustion device mounted on the vehicle.

[0002]

2. Description of the Related Art In general, a combustion device such as a water heater includes:
Various safety devices for safety measures are installed. The safety device includes, for example, a flame extinguishing safety device that detects the flame of the burner is extinguished or lifted by a flame rod and immediately stops the combustion. An overheat prevention device that closes the gas solenoid valve with a temperature fuse and shuts off gas when it becomes clogged, and an overpressure relief device that operates a blow valve to release pressure when the pressure inside the heat exchanger rises abnormally. And that the concentration of carbon monoxide (CO) in the exhaust gas has exceeded the set value due to incomplete combustion.
Also when the detection is performed by the sensor, control such as stopping the combustion is performed.

The operation of the water heater 1 provided with the above-described safety device will be described with reference to FIG. When a hot water tap (not shown) is opened, the water passes through the water quantity sensor 12 and is branched into the hot water heat exchanger 16 and the bypass passage 14. Hot water supply heat exchanger 1
The hot water heated in 6 and the water passing through the bypass passage 14 are mixed to reach a set temperature and flow to the hot water tap.

First, when the amount of water reaches a certain level or more, the water amount sensor 12 senses the flow rate. Then, the combustion fan 24 that sucks air from the air supply passage 50 and discharges the exhaust gas after combustion from the exhaust passage 52 rotates, and the prepurge starts. In the present embodiment, the combustion fan 24 is connected to the exhaust passage 52.
This is for uniformly dispersing the exhaust gas in the exhaust passage and accurately operating a CO sensor described later.

Subsequently, at the same time as the ignition of the ignition plug 18, the original gas solenoid valve 28 and the gas solenoid valve 30 are opened, and gas flows through the gas proportional valve 32.

Next, when the burner 22 is ignited, the flame rod 20 detects a fire and starts burning. If the ignition is not performed within a predetermined time, the safety circuit is activated, the original gas solenoid valve 28 and the gas solenoid valve 30 are shut off, and the discharge is stopped. When the tapping temperature changes due to a tapping amount, a tapping amount, a water pressure change, or the like during use of the tapping water, the input water thermistor 34, the tapping thermistor 36, and the water amount sensor 12 sense and calculate a set temperature difference using the tapping temperature, the input water temperature, and the water amount. Then, the deviation value is transmitted to the gas proportional valve 32 and the water amount control valve 38 to maintain the set temperature.

The combustion fan 24 is provided with a Hall IC 26 for detecting the number of revolutions of the fan, and the rotation of the combustion fan 24 determines the optimum air volume so as to generate complete combustion in accordance with the gas supply amount. Is controlled to be sent to

[0008] The CO sensor 40 is provided in an exhaust passage 52. When the CO gas concentration is detected to be equal to or more than the allowable value, first, the rotation speed of the combustion fan 24 is increased, and the rotation speed of the combustion fan is controlled so that complete combustion is performed by increasing the amount of air sent into the combustion chamber. . But,
If the CO gas concentration does not decrease and reaches a predetermined concentration or more despite the increase in the air volume, the combustion is stopped.

The CO sensor 40 is made of a platinum resistor having a specific catalyst around it which causes a chemical reaction with CO gas. When the catalyst causes a chemical reaction with CO gas, the temperature of the catalyst rises. The resistance value of the platinum resistor changed in response to the change is output. The output value of the CO sensor is controlled by a CO sensor substrate described later.
Converted to concentration.

[0010]

SUMMARY OF THE INVENTION
Since the output value changes over time, the output value shifts even at the same CO concentration. Therefore, the output value from the CO sensor 40 in which combustion is not performed is periodically measured in advance as a reference value, for example, a zero point value, and the measured value is stored in, for example, a memory provided in a microcomputer of a main body substrate that controls the combustion device. An accurate CO concentration is obtained by comparing the output value from the CO sensor 40 during combustion with the zero point value.

However, for example, the CO
When the sensor is replaced, the zero point value of the replaced CO sensor may not match the zero point value stored in the memory, and an accurate CO concentration may not be obtained.

As described above, when various detection means including the CO sensor are replaced, an inaccurate detection value may be detected.

Accordingly, an object of the present invention is to provide a means capable of accurately measuring a detected value even when a detecting means such as a CO sensor is replaced.

[0014]

SUMMARY OF THE INVENTION An object of the present invention comprises detecting means for detecting data used for operation of a combustion device, and control means for controlling the combustion device based on data from the detecting means. Wherein at least one of the control means and the detection means has identification data to be identified from the other, and the other includes identification means for identifying the identification data. This is achieved by:

The identification means has first storage means for storing the identification data, and the identification data stored in the first storage means and at least one of the detection means and the control means have Check with identification data.

Further, when the collated identification data is different from each other, the identification data of at least one of the detection means and the control means is stored in the first storage means.

When the identification data is not stored in the first storage means, the identification data of at least one of the detection means and the control means is stored in the first storage means.

As described above, when the identification data of at least one of the detection means and the control means is stored in the first storage means, the zero point value of the detection means is changed to the value of the detection means or the control means. Zero point value correction stored in the second storage means provided in the control means is performed, and combustion is not permitted until the zero point value correction is performed. A predetermined range is set for the zero point value, and the zero point value within the predetermined range is stored in the second storage means.

On the other hand, when the collated identification data matches or when the zero point value correction is performed, the combustion is permitted, and the CO for notifying that the combustion is permitted is provided.
Notification means such as a sensor lamp may be provided.

Further, when the zero point value of the detection means at a predetermined time during which combustion is not being performed and the zero point value stored in the second storage means are different from each other by a predetermined value or more, the stored value is stored in the second storage means. The zero point value is updated to the zero point value of the detection means at a predetermined time during which the combustion is not being performed,
This makes it possible to always obtain an accurate CO concentration.

Here, the identification data may be, for example, an ID number or a serial number assigned to each of the CO sensors, and the identification means for identifying the identification data may be, for example, the detection data. A communication line for connecting the control means with the control means via an interface; and a CPU and a memory of a microcomputer provided in the detection means or the control means.

The detecting means is, for example, a CO sensor, and the storage means is, for example, a rewritable nonvolatile memory such as an E ² PROM.

Further, it is an object of the present invention that the sensor zero point value or a predetermined reference value stored in the control memory of the combustion device is set to a zero point value or a predetermined reference value of a sensor attached to the combustion device. The value is confirmed, and if the confirmation is not performed, the zero point value or the predetermined reference value is stored in the memory, and the combustion is performed until the zero point value or the predetermined reference value is stored in the memory. This is achieved by providing a combustion device having a control means that does not permit the combustion.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. However, the technical scope of the present invention is not limited to this embodiment.

FIG. 1 shows a control block diagram of the CO sensor 40. The output value of the CO sensor 40 is the CO sensor 40
Is sent as an analog value to the CO sensor board 70 that controls In the CO sensor board 70, the output value is amplified by the amplifier circuit 71. A table of CO concentration values corresponding to predetermined output values is stored in a memory 73 composed of an E ² PROM, and the CPU 72 converts the CO concentration values from the output values and finds them.

The value of the obtained CO concentration is transmitted via an interface 74 to a main body substrate 80 which is a control substrate of the combustion apparatus.
And stored in a rewritable nonvolatile memory 83 such as an E ² PROM provided on the main body substrate 80.
When the CO concentration exceeds a set allowable range that is dangerous to the human body, the main body substrate 80 activates a necessary actuator 94 to stop the combustion.

According to the embodiment of the present invention, the output value of the CO sensor 40 when combustion is not being performed is stored in the memory 83 of the main body substrate 80 as a reference value, that is, a zero point value. Then, the zero point value is measured at an appropriate time, for example, when the power of the combustion apparatus is turned on and after a certain time has elapsed after the end of combustion, and the measured value is stored in the memory 83 of the main body substrate 80. If it is different from the point value, zero point correction is performed by rewriting the zero point value as appropriate. Thereby, the main body substrate 8
By calculating the difference between the output value from the CO sensor 40 during combustion and the corrected zero point value by the CPU 82 of 0, an accurate CO concentration can be obtained. Thereby, it is possible to cope with the secular change of the sensitivity of the CO sensor 40, and it is possible to obtain an accurate CO concentration.

Here, the output value of the CO sensor 40 is stored on the main board as, for example, an 8-bit digital value. Normally, the zero point value is an output value of the CO sensor in a non-combustion state in which almost no CO exists, and the range of the output value is limited to some extent even if a shift due to aging is considered. Therefore, the digital value related to the zero point value is given a range of a predetermined vertical width.

In an initial state such as the time of shipment from a factory, the initial value is usually written in the memory 83 of the main body substrate 80 by the first measurement of the zero point value. If, for example, two or more digits deviate from each other, the zero point value stored in the memory of the main body substrate 80 is rewritten. In addition, rewriting is not performed because a deviation of one digit is not a large error.

When the zero point value of the CO sensor 40 is rewritten due to aging as described above, the CO sensor may be replaced together with the CO sensor board 70 by a service such as maintenance. At this time, the zero point value of the replaced new CO sensor 40 is the initial value before correction. On the other hand, the zero point value stored in the memory of the main body substrate 80 remains the correction value of the old CO sensor before replacement. Therefore, by pressing a clear switch (not shown) provided on the main body substrate 80 at the time of replacement, the zero point value stored in the main body substrate 80 is cleared once, and the zero point value newly measured before the combustion is performed is changed. Was stored in the memory again.

However, if the clear switch is not pressed, the old CO is kept until the above-mentioned zero point correction is performed.
The zero point value of the sensor remains stored in the memory of the main body substrate 80. Therefore, if combustion is performed below this zero point value, an incorrect CO concentration may be measured.

Therefore, according to another embodiment of the present invention, the following means is provided. First, for example, an ID number for identifying an individual CO sensor is written in the memory 73 of the CO sensor substrate 70 in FIG. Then, the main body board 80 reads the ID number through the communication line 90 and stores the ID number in the rewritable nonvolatile memory 83 such as an E ² PROM of the main body board 80.

Further, when the CO sensor 40 is operated, the main body substrate 80 is first placed on the CO sensor substrate 7.
The ID number stored in the memory 73 of “0” is read,
It is confirmed whether or not the ID number matches the ID number stored in the memory 83 of the main body substrate 80. If they are different, by forcibly correcting the zero point before starting the combustion, an accurate CO concentration can be measured even when the CO sensor is replaced. Further, since the ID numbers do not match when the main body substrate 80 is replaced, zero point correction is performed.

Further, the CO sensor substrate 70 is
0, the ID number stored in the memory 83 is read,
It may be confirmed whether or not the ID number matches the ID number stored in the memory 73 of the CO sensor board 70, and the same zero point correction as described above may be performed.

FIG. 2 is a flowchart showing the present embodiment. This will be described with reference to the block diagram of FIG.

First, the power switch of the combustion device is turned on,
When the CO sensor 40 is energized (step S1), the ID number of the CO sensor 40 stored in the memory 73 of the CO sensor substrate 70 is transmitted to the main body substrate 80 via the interface 74, the communication line 90, and the interface 81. Can be Then, it is confirmed whether or not the value of the previously measured zero point is stored in the memory 83 of the main body substrate 80 (step S2). Memory of zero point is stored in memory 8
The determination is made based on whether or not the zero point flag has been set at 3. If there is no zero point value, a zero point value is obtained in step S4 described below. If there is a zero point value, the ID number of the CO sensor 40 stored in the memory 83 of the main body substrate 80 is compared with the transmitted ID number (step S3). In addition, wireless communication may be used as a communication unit between the main body substrate 80 and the CO sensor substrate 70.

If the ID numbers match, the CO sensor lamp provided in the combustion device is turned on to indicate that the combustion apparatus is in a combustible state (step S5).

If the ID numbers do not match, or if the above-mentioned zero point value is not stored, in step S4, the CO sensor substrate when the CO concentration of the CO sensor 40 is zero (non-combustion) is forcibly set. The output value from 70 is acquired as a zero point value, and the zero point value is stored in the memory 83 in the main body substrate 80. If the ID numbers do not match, the C value in the CO sensor board 70 is stored together with the storage of the zero point value.
The ID number of the O sensor is acquired and stored in the memory 83 in the main body substrate 80.

Through these steps S3, S4, and S5, even if the CO sensor 40 or the main board 80 is replaced, it is guaranteed that the zero point values of both are always the same. CO concentration can be measured.

FIG. 3 is a flowchart of the correction of the zero point value performed in step S4. After a predetermined time such as 20 seconds elapses until the state of energization to the CO sensor 40 is stabilized (step S41), the output value from the CO sensor is measured (step S42). The output value from the CO sensor is detected, for example, every 0.1 seconds, and the zero point value digitized by the CO sensor
And temporarily stored in a memory (not shown) such as a RAM, and the CPU 82 calculates an average value of the measurement for 10 seconds. The reason for obtaining the average is to smooth out the variation in the output from the CO sensor.

As described above, since the CO sensor deteriorates with aging, when the zero point value is out of an appropriate range, it is necessary to determine that the CO sensor itself is defective. Therefore, an appropriate range of the zero point value is set in advance to, for example, a range of 40 digits above and below the initial value. If the measured zero point value is within the set allowable range, the zero point is determined to be a valid value (step S).
43), the zero point value is stored in the memory 83 (step S44).

On the other hand, if the measured zero point value is out of the set allowable range due to the abnormality of the CO sensor 40 or the CO sensor substrate 70, the zero point value is determined to be invalid, and is re-checked for 10 seconds just in case. The average value of the output of the CO sensor 40 is calculated, and the validity of the value is determined (step S4).
5). If valid, the value is stored in the memory 83,
If invalid, an error signal is generated (step S4).
6) Do not allow combustion.

Returning to FIG. 2, in step S5, C
When the O sensor obtains the correct zero point value, the main board 8
0 and C provided on a remote controller for operating the same.
A display unit such as an O sensor lamp is turned on, the combustion is enabled, and the apparatus enters a combustion command standby state. After the combustion is enabled, the detection of the zero point value is continued for 2 hours after the power is turned on. If there is no combustion command, the detection of the zero point value is terminated after the lapse of 2 hours. Rewrite the value. When a combustion command is issued, the zero point value immediately before the start of combustion is taken into the main body substrate 80 to start combustion. Further, after the end of the combustion, one hour and three hours after the lapse of 30 minutes from the end of the combustion.
The detection of the zero point value is continued for 0 minutes, and when there is no combustion command, the detection of the zero point value is terminated after 1 hour and 30 minutes, and the zero point value is rewritten if necessary.

In step 6 of FIG. 2, it is determined whether or not there is a combustion command. If there is no combustion command, the CO sensor is energized for 2 hours after the power is turned on, during which time the CO sensor continues to output (step 6). S7). If there is no combustion command for two hours (steps S8 and S9), step S1
At 0, it is determined whether to rewrite the zero point stored in the memory 83.

FIG. 4 shows a flowchart for rewriting the zero point value. The average of the CO sensor output values for the last 10 seconds immediately before the lapse of 2 hours is calculated, and the validity of whether or not the output value is within the set allowable range is determined in the same manner as in step 43 (step S101). If the value is not a valid value, the output value for 10 seconds is calculated again, and the validity is determined again (step S102). If the value is invalid, an error signal is generated as described above (step S10).
3).

On the other hand, step S101 or step S1
In 02, when a valid zero point value is obtained, the value is compared with the zero point value stored in the memory 83 (step S104). Then, the zero point value stored in the memory 83 is rewritten to a new zero point value (step S105). Further, the deviation of one digit is determined to be an allowable error, and is not rewritten.

Returning to FIG. 2, when the process of step S10 is completed, a combustion standby state where no zero point value is detected is entered (step S18). When a combustion command is issued, the process proceeds to step S11 described later.

In step S8, if a combustion command is issued two hours before the lapse of two hours, then at step S1
Step 0 is performed, and combustion is started based on the latest zero point value of the CO sensor.

If a combustion command is issued before the CO sensor lamp is turned on, combustion starts at the same time as the CO sensor lamp is turned on (step S11). When the combustion is completed (step S12), the CO sensor is kept energized for a certain period of time, for example, two hours, as in the case where there is no combustion command. During this time, there is an output from the CO sensor, but for a certain time, for example, 30 minutes after the combustion is stopped, C
Since the output from the O sensor is not stable, it is not used as a zero point correction value. Therefore, if the combustion command is issued again before the lapse of 30 minutes (step S13), the combustion is started without performing the process of step S10.

After 30 minutes have passed since the combustion was stopped (step S14), when a combustion command was issued (step S14).
16) Or, if one hour and thirty minutes have elapsed after the combustion was stopped (step S17), the output from the CO sensor 40 is also stable, so the step S10 is performed as described above, and the zero point is corrected. Is performed. When the operation of step S10 is completed as described above, the process enters a combustion standby state in which a zero point value is not detected (step S18).

In the present invention, when the ID numbers do not match and when the value of the above-mentioned zero point is not stored,
Instead of performing the zero point value correction flow in step S4 of the above-described flowchart, a predetermined zero point initial value determined from the safe side such that the CO concentration increases may be given. As a result, it is possible to enter a state ready for combustion,
An accurate zero point value is given by the zero point rewriting flow in step S10 performed after the end of combustion.

In the above-described embodiment of the present invention, the embodiment of the CO sensor has been described.
The present invention is not CO sensors only, e.g., gas sensor and air flow, such as NO _x sensor, can be used in a variety of sensors such as wind speed sensors.

The zero point value correction may be a predetermined reference value other than the zero point.

[0054]

As described above, according to the present invention, C
Identification data such as an ID number is written to the O-sensor board, and the identification data is stored in a rewritable nonvolatile memory such as an E ² PROM of the main body board. Thereby, even when the zero point value of the CO sensor is stored in the memory of the main body substrate, if the identification data read by the main body substrate is different from the data stored in the memory, the zero point value of the CO sensor is stored. Point value correction is performed. Therefore, there is no need to operate the clear switch for clearing the zero point value, which had to be manually performed when replacing the CO sensor, and even if it is not cleared, an accurate CO concentration can be obtained. It is possible.

[Brief description of the drawings]

FIG. 1 is a control block diagram of a CO sensor.

FIG. 2 is a flowchart showing an embodiment of the present invention.

FIG. 3 is a flowchart of zero point value correction.

FIG. 4 is a flowchart of rewriting a zero point value.

FIG. 5 is a diagram illustrating a configuration of a water heater that is an example of a combustion device.

[Explanation of symbols]

 40 CO sensor 70 CO sensor board 73 memory 80 body board 83 memory

Claims (14)

[Claims] A detecting means for detecting data used for the operation of the combustion apparatus; and a control means for controlling the combustion apparatus based on data from the detecting means, wherein at least one of the control means and the detecting means is provided. A combustion apparatus characterized in that one has identification data to be identified from the other, and the other includes identification means for identifying the identification data. 2. The identification means has first storage means for storing the identification data, and the identification data stored in the first storage means and at least one of the detection means and the control means are provided. The combustion device according to claim 1, wherein the combustion device is compared with identification data. 3. The apparatus according to claim 2, wherein when the collated identification data is different from each other, the identification data of at least one of the detection means and the control means is stored in the first storage means. A combustion device as described. 4. When the identification data is not stored in the first storage means, the identification data of at least one of the detection means and the control means is stored in the first storage means. The combustion device according to claim 2, wherein 5. When the identification data of at least one of said detection means and said control means is stored in said first storage means, a zero point value of said detection means or a predetermined reference value is set to said detection means or said reference value. 5. The combustion apparatus according to claim 3, wherein the zero point value correction or the reference value correction stored in the second storage means provided in the control means is performed. 6. The combustion is not permitted until the zero point value correction or the reference value correction is performed.
The combustion device according to claim 1. 7. When the collated identification data matches or when the zero point value correction or the reference value correction is performed,
The combustion device according to claim 2, wherein combustion is permitted. 8. The combustion apparatus according to claim 7, further comprising notification means for notifying that combustion has been permitted. 9. When a zero point value or a predetermined reference value of said detection means at a predetermined time during which combustion is not being performed is different from a zero point value or a predetermined reference value stored in said second storage means by a predetermined value or more. The zero point value or a predetermined reference value stored in the second storage means is updated to a zero point value or a predetermined reference value of the detection means during a predetermined time when the combustion is not being performed. Item 9. The combustion device according to item 7 or 8. 10. A predetermined range is set for the zero point value or the predetermined reference value, and a zero point value or a predetermined reference value within the predetermined range is stored in the second storage means. The combustion device according to claim 5 or 9, wherein 11. A combustion apparatus according to claim 1, wherein said detection means is a carbon monoxide gas sensor. 12. The combustion apparatus according to claim 1, wherein said storage means is a rewritable nonvolatile memory. 13. The combustion apparatus according to claim 8, wherein said notification means is a carbon monoxide gas sensor lamp. 14. Confirmation that a zero point value or a predetermined reference value of a sensor stored in a control memory of the combustion device is a zero point value or a predetermined reference value of a sensor attached to the combustion device. When the confirmation is not performed, the zero point value or the predetermined reference value is stored in the memory, and a control unit that does not permit the combustion until the zero point value or the predetermined reference value is stored in the memory is provided. A combustion device comprising: