JP3441171B2 - Method and apparatus for detecting exhaust CO concentration of CO detection sensor installed in combustion equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CO gas (carbon monoxide gas) contained in an exhaust gas of a combustion device installed in the combustion device.
The present invention relates to a method for detecting the exhaust CO concentration of a CO detection sensor that correctly detects the concentration of CO, and an apparatus for performing the method.

[0002]

2. Description of the Related Art CO is provided on the exhaust side of combustion equipment such as a water heater.
A CO detection sensor is provided in order to prevent danger due to generation of gas.

An example of a CO sensor generally known as this type of CO detection sensor is shown in FIGS. 5 and 6. In these figures, two pairs of terminal pins 2 are provided on the upper surface of the base 1, and a diameter of 10 μm is provided between each pair of terminal pins.
A comparison element 4 which is insensitive to CO gas and a detection element 5 which is sensitive to CO gas are provided through a thin platinum wire of m, and the comparison element 4 and the detection element 5 are separated by a partition plate 6.

Around these comparison element 4 and detection element 5,
It is covered with a cylindrical glass wool 7 having open upper and lower end surfaces, and the outer side thereof is covered with a metal cover 8. A blade-shaped plate 10 is formed by cutting and raising on the inner surface of the peripheral wall of the metal cover 8, and the exhaust gas is formed so as to enter the inside through a cut-and-raising opening 11.

The comparison element 4 and the detection element 5 are incorporated in a resistance bridge circuit as shown in FIG. The comparison element 4 and the detection element 5 perform the CO gas detection period, that is, during the combustion of the combustion equipment and the post-purge period of about 5 minutes after the combustion is stopped (the period when the combustion fan is continuously rotated after the combustion is stopped). , In order to keep the element operation stable, it is heated to about 200 ℃ by energization. In this state, when CO gas comes into contact with the detection element 5, a catalytic combustion reaction occurs, and this reaction causes the temperature of the detection element 5 to rise. It rises and electric resistance increases. Due to this resistance change, the equilibrium state of the bridge circuit is lost, and the current change due to the loss of balance is converted into a voltage change, which is taken out as a CO detection signal.

Generally, the sensor output of the CO sensor depends on the CO concentration and the hydrogen gas (H ₂ gas) concentration in the exhaust gas. As described above, the sensor output of the H ₂ gas is added to the sensor output of the CO concentration in the exhaust gas, which results in a problem that the CO output in the exhaust gas cannot be accurately detected by the sensor output. For this reason, normally, as shown in FIG. 3, the relational graph data between the sensor output of the CO sensor in the exhaust gas and the true CO concentration in the exhaust gas is previously set in advance.
For example, a fuel gas such as 13 A of city gas is made as a representative, and the sensor output detected from the CO sensor is compared with this graph data. For example, when the sensor output is V _D , the CO concentration in the exhaust gas is Is detected as U _D ppm.

[0007]

The fuel for combustion equipment is
In addition to gases such as 6A, 6B, and 13A, various gases such as butane gas and propane (LPG) gas are used.
The present inventor measured the concentration of H ₂ gas contained in the exhaust gas when burning these various gases. As a result, it was found that the H ₂ concentration in the exhaust gas differs depending on the gas species.

Conventionally, assuming that the H ₂ gas concentration in the exhaust gas does not differ depending on the combustion gas item (gas type), the relationship data between the sensor output and the exhaust CO concentration as shown in FIG. Was required. But for example,
As shown in FIG. 4, when the gas type of the fuel is different, the CO concentration in the exhaust gas is different even if the value of the sensor output is the same. For example, when the sensor output is V _b , 6B gas and propane A difference in CO concentration of ΔU _b occurs between the gases, and also when the sensor output is V _a , a difference in CO concentration of ΔU _a occurs between the gas of 6B and the propane residue.
In the method of using the graph data of the relationship between the sensor output and the CO concentration in the exhaust gas, which is obtained by using one type of representative gas, variations occur for different gas types,
We faced the problem of not being able to accurately detect the CO concentration in the exhaust gas.

The present invention has been made to solve the above problems, and an object thereof is to install a combustion device capable of detecting an accurate CO concentration in exhaust gas regardless of the type of gas used. An object is to provide an exhaust CO concentration detection method for a CO detection sensor and an apparatus therefor.

[0010]

In order to achieve the above object, the present invention is constructed as follows. That is, the method of the present invention, seeking CO concentration component in the exhaust gas of the combustion equipment for each advance fuel type relationship data between the sensor output and the C O concentration of CO sensor for detecting comprise concentration of H ₂ component Given that the fuel used for combustion is initially set, the combustion operation is performed, the sensor output of the CO detection sensor is compared with the set fuel type relation data, and the sensor output value of the relation data is set. It is characterized in that the corresponding CO concentration value is detected as the actual CO concentration value in the exhaust gas.

Further, the device of the present invention detects the CO concentration component in the exhaust gas of the combustion equipment by including the H ₂ concentration component in the C component.
A memory in which relational data between the sensor output of the O detection sensor and the CO concentration is obtained and stored for each fuel type, a fuel type input setting unit for externally setting the fuel type used for combustion, and CO detection CO concentration confirmation detection that compares the sensor output of the sensor with the relational data of the set fuel type and outputs the value of the CO concentration corresponding to the sensor output value of the relational data as the value of the actual CO concentration in the exhaust gas. And a part.

[0012]

In the present invention having the above-described structure, the CO concentration in the exhaust gas is detected by the CO detection sensor during the combustion operation of the combustion equipment, and the sensor output is added to the CO concentration determination detecting section. Before this combustion operation is performed, for example, at the stage of factory shipment of the combustion equipment, the fuel type used by the destination is input and set in advance by the fuel type input setting unit, and the true CO 2 in the exhaust gas is set. The relationship data between the concentration and the sensor output is stored in the memory for each fuel type,
The CO concentration confirmation detection unit compares the sensor output of the CO detection sensor with the relational data of the fuel type that is input and set, and determines the CO concentration value corresponding to the sensor output value of the relational data as the actual CO concentration in the exhaust gas. Concentration value (measured value of CO concentration)
Output as. As described above, in the present invention, since the relationship data between the sensor output and the CO concentration is given for each fuel type used, it is possible to accurately detect the CO concentration in the exhaust gas according to the fuel type used. Become.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. In the description of the present embodiment, the same names as those in the conventional example are designated by the same reference numerals, and the duplicate description thereof will be omitted. The combustion device of the present embodiment is intended for a water heater as in the conventional example, and the same CO as in the conventional example is provided on the exhaust side of the water heater.
A CO sensor as a detection sensor is installed. Further, in this embodiment, a characteristic CO concentration determining means for outputting an accurate CO concentration in exhaust gas according to the fuel type (gas type) used is provided based on the sensor output of the CO sensor. Has been.

As shown in FIG. 1, the characteristic CO concentration determining means in this embodiment comprises a CO concentration determination detecting section 12, a memory 13, and a fuel item input setting section 14.

As shown in FIG. 2, in the memory 13, relational data between the sensor output of the CO sensor and the true CO concentration in the exhaust gas is obtained in advance for each fuel type (gas type). It is stored as graph data. The sensor output on the vertical axis of this graph is the output of CO concentration in the exhaust gas and H
The output of the _two concentrations is included, and the horizontal axis of the graph accurately represents the true CO concentration in the exhaust gas. By preparing this graph, even if the output of the H ₂ concentration is added to the output of the CO concentration in the sensor output, the correct CO concentration can be read from the sensor output value.

The fuel type input setting unit 14 is composed of, for example, a gas type changeover switch or the like. Normally, a water heater or the like is provided with a gas type changeover switch,
The gas type to be used is switched and set by this gas type changeover switch, and the maximum valve opening drive current corresponding to the maximum combustion capacity of the proportional valve (the valve that controls the amount of fuel gas supplied to the burner by the valve opening amount) is set. The minimum valve opening drive current corresponding to the minimum combustion capacity is adjusted and set, and in this embodiment, the gas type changeover switch is made to function as the fuel type input setting section 14.

The CO concentration determination detector 12 takes in the sensor output of the CO sensor, while the fuel type input setting unit 12
The fuel type input, that is, the gas type, is confirmed in 14 and the relationship graph data between the sensor output and the CO concentration in the exhaust gas of the gas type input and set is read from the memory 13. Then, from the graph of the read relational data, the CO in the exhaust gas corresponding to the sensor output of the CO sensor
The concentration value is read, this value is determined as the actual measurement value of the CO concentration in the exhaust gas, and this determined value is added to the CO safety device 15 and the like.

For example, in FIG. 2, when the gas type is 6B, the sensor output is V _b3 , when the gas type is 13 A, the sensor output is V _b2 , and the gas type is propane (LP).
In the case of G), when the sensor output is V _b1 , the CO concentration in the exhaust gas is fixed as U _b (ppm) in both cases.
Similarly, when the gas type is 6B, the sensor output is V _a3 , when the gas type is 13 A, the sensor output is V _a2 , and when the gas type is propane gas, the sensor output is V _a1 , the exhaust gas. The CO concentration in the inside is confirmed as U _a (ppm), and this confirmed value is C as the measured CO concentration in the exhaust gas.
It is added to the O safety device 15, etc.

The CO safety device 15, for example, stops combustion of the water heater when the value of the definite CO concentration exceeds a preset dangerous value, or adds up the definite value of the CO concentration every time it is sampled. CO safe operation is performed in various processing modes, such as stopping combustion when the integrated value reaches a preset dangerous concentration.

According to the present embodiment, the relationship graph data between the sensor output and the CO concentration in the exhaust gas is given in advance for each gas type used, and the relationship data of the gas type used is obtained from the sensor output of the CO sensor. Since the actual measurement value of the CO concentration in the exhaust gas is determined by using, the CO concentration in the exhaust gas can be accurately detected according to the type of gas used, and the CO safety operation of the CO safety device 15 can be accurately performed. Therefore, the reliability of CO safe operation can be improved.

The present invention is not limited to the above-mentioned embodiment, and various embodiments can be adopted. For example, in the above-described embodiment, the catalytic combustion reaction type CO sensor as shown in FIGS. 5 and 6 is used as the CO detection sensor.
Other types of CO sensors may be used, or O
_{A 2} sensor or a CO ₂ sensor may be used as the CO detection sensor. In these cases, the relationship data between the sensor output and the CO concentration in the exhaust gas is obtained for each gas type and stored in the memory 13 according to the CO detection sensor used.

Further, in the above embodiment, the relational data between the sensor output and the CO concentration in the exhaust gas is given as graph data, but this may be given as table data, or an arithmetic expression (arithmetic expression data) may be given. ) May be given.

Further, in the embodiment, as the gas species, 6B,
13A, propane (LPG) was used as an example, but 6
It is also applied to various other gas species such as A and butane.

Further, in the above-mentioned embodiment, the hot water supply device is explained as the combustion device, but it is applied to various other combustion devices using gas as fuel, such as bath heaters, air conditioners, air conditioners, and heaters. It is something.

[0025]

INDUSTRIAL APPLICABILITY The present invention provides CO for each fuel type of combustion equipment.
The relational data between the sensor output of the detection sensor and the CO concentration in the exhaust gas is obtained and given, and the sensor output output from the CO detection sensor during the combustion operation of the combustion equipment is used for combustion. Since the value of the CO concentration in the exhaust gas corresponding to the sensor output is obtained as the measured value using the relational data, the proportion of H ₂ gas in the exhaust gas differs depending on the type of fuel used. Also, the CO concentration in the exhaust gas can be accurately detected without being affected by the variation in the H ₂ gas concentration between the gas species, and the CO safe operation can be performed based on the accurate detected value of the CO concentration. Can be performed accurately, and the reliability of CO safety can be significantly improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of relational graph data between each gas type and CO concentration in exhaust gas stored in the memory of FIG.

FIG. 3 is an explanatory diagram of single graph data of a sensor output of a CO sensor provided to a conventional combustion device and a CO concentration in exhaust gas.

FIG. 4 is an explanatory diagram showing variations in CO detection concentration of a CO sensor depending on gas species.

FIG. 5 is a diagram illustrating the configuration of a general CO sensor.

FIG. 6 is an explanatory diagram of a state where the CO sensor of FIG. 5 is disassembled.

7 is a circuit diagram of CO detection of the CO sensor shown in FIG.

[Explanation of symbols]

12 CO concentration confirmation detector 13 memory 14 Fuel type input setting section 15 CO safety device

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01N 27/00-27/24 F23N 5/24-5/24 113 G08B 19/00-21/00

Claims (2)

(57) [Claims] 1. The relational data between the CO output and the sensor output of a CO detection sensor that detects the CO concentration component in the exhaust gas of a combustion device including the H ₂ concentration component is obtained and given in advance for each fuel type. , The combustion operation is performed after the fuel type used for combustion is initially set, the sensor output of the CO detection sensor is collated with the set relation data of the fuel type, and the CO output corresponding to the sensor output value of the relation data is detected. An exhaust CO concentration detection method for a CO detection sensor installed in a combustion device, which detects a concentration value as an actual CO concentration value in exhaust gas. 2. A stored relationship data between the sensor output and the C O concentration of CO sensor the CO concentration component in the exhaust gas of the combustion equipment for detecting comprise concentration of H ₂ component is obtained for each fuel type Memory, the fuel type input setting section for externally setting the fuel type used for combustion, and the sensor output value of the related data by comparing the sensor output of the CO detection sensor with the related data of the set fuel type. CO concentration confirmation detecting section for outputting the value of the CO concentration corresponding to the value as the value of the actual CO concentration in the exhaust gas C
Exhaust CO concentration detection device of O detection sensor.