JPH052265B2 - - Google Patents

Description

Detailed Description of the Invention [Terminology] In this specification, an increase in the gas sensor output refers to a change in the sensor output corresponding to the progress of air pollution, and a decrease or reduction in the sensor output refers to a change in the sensor output corresponding to the progress of air pollution. Indicates the change in sensor output on the side that corresponds to purification.

[Field of Application of the Invention] The present invention relates to air conditioning control using a gas sensor.

[Prior art] JP-A No. 60-27849 proposes that the minimum value of the gas sensor output during a predetermined sampling period is used as a reference output corresponding to clean air, and that atmospheric contamination is detected by comparing with this output. are doing. In this way, it is possible to avoid the influence of daily fluctuations in the sensor or fluctuations in the sensor output unrelated to air pollution due to temperature and humidity. Further, there is no need to adjust the gas sensitivity of each individual sensor.

However, in reality, the problem of sampling the reference output has not been solved. For example, if the minimum value of the sensor output is used as the reference output without any restriction, excessive air conditioning will occur and the user will feel uncomfortable. Conversely, if a higher sensor output is used as the reference output, air conditioning will be incomplete. Furthermore, the sensor output has variables unrelated to air pollution due to factors such as humidity fluctuations. This further complicates the problem of sampling the reference output.

[Problem of the Invention] An object of the present invention is to perform appropriate air conditioning by sampling an appropriate reference output.

[Structure of the Invention] The air conditioning control device of the present invention includes a gas sensor for detecting atmospheric pollution, a storage means for storing the minimum value of the gas sensor output in a predetermined period as a reference output, and a storage means for storing the minimum value of the gas sensor output in a predetermined period as a reference output. In an air conditioning control device equipped with a contamination detection means for operating an air conditioning load based on a comparison value with the output, it is prohibited to change the reference output when the air conditioning load is operating, and the gas sensor output at the end of operation of the air conditioning load is The present invention is characterized in that it includes a reference value changing means that sets the reference output regardless of a predetermined period.

Here, the sensor output at the end of air conditioning load operation is:
It means the output when the air is sufficiently purified within the capacity of the air conditioning load. Therefore, if the output at this point is used as the reference output, good air conditioning control can be achieved. In addition, the effects of pollution of the outside air itself, fluctuations in humidity, etc. are corrected by using the output at this point as a reference.

An example in which a microcomputer is used and an air cleaner is used as the air conditioning load will be described below, but the present invention is not limited to this, and appropriate changes can be made within the range of known techniques.

[Example] The hardware of the apparatus will be explained in FIG. 1. In the figure, 2 is an AC power source, 4 is a transformer, and 6 is a gas sensor, in which an electrode 10 that also serves as a heater and another electrode 12 are embedded in a metal oxide semiconductor 8 such as SnO ₂ . The electrical conductivity of the gas sensor 6 increases with air pollution, and this is used as an output. 14 is a load resistor, 16 is a diode for half-wave rectification, 18 is a resistor, and 20 is a capacitor, and the sensor output is taken out to the capacitor 20. Further, from the transformer 4, an unstable DC power source A and a stabilized DC power source B are taken out.

22 is a comparison circuit, 24 is a microcomputer for air conditioning control, 26 is a capacitor, and 27 is an NTC.
It is a thermistor. The thermistor 27 is used to compensate for fluctuations in the sensor output due to temperature fluctuations and to reduce the capacity of the microcomputer 24 required for A/D conversion. 28 is the sensitivity switch,
For example, it is configured to select between a high-sensitivity switch and a low-sensitivity switch, and is input to the microcomputer 24 from the input terminal _I3 . Here, the input terminal _I2 of the microcomputer 24 is periodically grounded to discharge the charge in the capacitor 26. After the start of charging the capacitor 26, the time until the comparison potential of the comparison circuit 22 is reached is counted using the signal from the input terminal _I1 . This count is proportional to the sensor resistance. Note that Re is a reset terminal of the microcomputer 24.

30 is an interface with air conditioning equipment, 32 is a group of light emitting diodes for display, such as a light emitting diode LED1 for standby display, a light emitting diode LED2 for cleanliness display, and a light emitting diode for pollution display.
It is made up of LED3.

34 is an air cleaner as an air conditioning load.

The internal configuration and operation of the device will be explained with reference to FIG. When the power is turned on, there is a wait of about 2 minutes until the characteristics of sensor 6 stabilize, and during this time the light emitting diode
A standby display is performed using LED1. Next, read the sensor resistance Rs and store it in the memory M ₁ , M ₂ as the initial value.
to be memorized. Here, M ₁ is the reference resistance value, based on which the air purifier is controlled, and M ₂ is the maximum resistance value in the current section.

After that, the sensor resistance is constantly read at intervals of about 2 seconds, and if the sensor resistance is _M2 or more,
Set M ₂ = Rs, and find the maximum resistance value in that section. If M ₁ <M ₂ , that is, the sensor resistance increases beyond the reference resistance value, M ₁ =M ₂ is immediately set.
An increase in sensor resistance means purification of the air, and the resistance value corresponding to the cleanest atmosphere is used as a reference, and this means is used as a priority change means. Next, the sensor resistance is compared with M ₁ K to detect air pollution. Here K is the sensitivity by switch 28,
K shall be 1 or less. If no contamination is detected, this loop is repeated until a predetermined period of, for example, about 10 minutes has elapsed, and when the period has elapsed, the reference resistance value is updated. Here, using the allowable width detection means,
M ₁ /M ₂ <J (J is a constant indicating the allowable width and is 1 or more)
In this case, the reference resistance value is updated to M ₁ = M ₂ . This is to prevent using a contaminated state as a reference. Note that if the update condition is simply set as M ₁ <M ₂ , it will not be possible to cope with gradual increases in sensor output due to changes in humidity, etc., resulting in unnecessary operation of air conditioning equipment.

When it detects pollution, it switches the light-emitting diode display, turns on the fan, and activates the air purifier. Next, the air cleaner is operated until the sensor resistance increases, after which a timer for about 5 minutes is activated, and then the air cleaner is stopped and the display of the light emitting diode is changed. The sensor resistance at this point corresponds to the sensor resistance at the time when air conditioning is advanced most. Therefore, using this as a new reference resistance value, M ₁ ,
Store in M ₂ and return to the original loop. Note that factors such as humidity fluctuations are automatically compensated for by using the resistance value at the end of the air purifier's operation as a reference.

Turning to FIG. 3, the vertical axis shows the sensor output, and the horizontal axis shows the section T. Here, the reference output changes as shown by the broken line in the figure, and when the sensor output decreases, it follows immediately, and when the sensor output increases, it follows only a gradual increase. For example, it does not follow the rather rapid increase in sensor output in section 4 to 5. This is to prevent the pollution state from being used as a standard. When the sensor output increases above the contamination detection level in section 5 and beyond, the air purifier operates after the output decreases until the timer ends. During this time, the reference output is not updated, and the output at the end of the air purifier operation is memorized as the reference output.

In the embodiment, the ratio between the sensor resistance and the reference value is used, but a difference may be used instead of the ratio, and the timing at which the operation of the air conditioning load ends can be freely changed.
For example, the contamination detection level and the operation end level may be different, and another air conditioning load such as a ventilation fan may be used instead of the air purifier.

[Effects of the Invention] In the present invention, the sensor output at the end of the operation of the air conditioning load is used as the reference output, and air conditioning control can be performed using an appropriate reference output.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of the air conditioning control device of the embodiment, Figure 2
The figure is a control flowchart, and FIG. 3 is a characteristic diagram showing its operating characteristics.

Claims (1)

[Scope of Claims] 1. A gas sensor for detecting atmospheric pollution, a storage means for storing the minimum value of the gas sensor output in a predetermined period as a reference output, and a comparison value between the gas sensor output and the reference output. In an air conditioning control device equipped with a contamination detection means for operating an air conditioning load, it is prohibited to change the reference output when operating the air conditioning load,
An air conditioning control device comprising a reference value changing means for setting a gas sensor output at the end of operation of an air conditioning load as a reference output regardless of the predetermined period. 2. In the air conditioning control device according to claim 1, priority changing means detects that the gas sensor output has decreased below the reference output and updates the gas sensor output as the reference output regardless of the predetermined period. An air conditioning control device characterized by being provided with. 3. In the air conditioning control device according to claim 2, when it is detected that the minimum value of the sensor output during a predetermined period when the air conditioning load is stopped increases by more than a permissible range with respect to the reference output, the reference output is adjusted. An air conditioning control device, characterized in that it is provided with an allowable width detection means for prohibiting changes in the width of the air conditioner.