JPH03296414A - Air cleaner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an air cleaner for use in a general household or automobile, which detects air pollution using a sensor and purifies the air depending on the dirt.

BACKGROUND ART In recent years, air cleaners that use sensors to detect air pollution and control their operation have become mainstream.

Conventionally, this type of air purifier uses a gas sensor whose resistance value changes depending on the gas concentration, and detects the degree of air pollution from the amount of change in the resistance value of this gas sensor. It was purifying the air. Also,
The degree of change in resistance value of a gas sensor with respect to gas concentration is determined by first setting the resistance value at a certain gas concentration (air that is considered to be clean) as a reference resistance value RO, and then calculating the amount of change in resistance value H at the current gas concentration with respect to this value. The degree of air pollution was determined from the

Problems to be Solved by the Invention In such conventional air purifiers, the resistance value at the gas concentration, which is the standard for the gas sensor, varies from several ohms to several hundred ohms, so it is difficult to measure the resistance value accurately over a wide range. There was a problem that I had to deal with. Therefore, in order to detect gas #11 degrees with accuracy above a certain level, it was necessary to use a high-precision device.

For example, if the reference resistance value is a number of ohms and a precision of 8 bits of resolution is required, to capture hundreds of ohms with the same resolution, an additional 7 bits are required, for a total of 16
This required a pit, which resulted in high costs. Also, if you reduce 15 bits to 10 bits, there will be 3 bits per ohm, which poses the problem of poor gas concentration detection accuracy.

In addition, there were cases in which sensors were selected and used so that the reference resistance [direction] fell within a certain value range, and a process was added in which the sensor was manually adjusted.

The present invention solves the above-mentioned conventional problems, and by fixing the output level at a certain reference resistance value and detecting the amount of change relative to this value, the amount of change in gas is detected, and the variation in the base resistance value is detected. The purpose is to provide a safe and highly reliable air purifier that always determines the degree of air pollution with a constant resolution (e.g., 8 bits) regardless of the air quality.

Means for Solving the Problems In order to achieve the above objects, the present invention provides a sensor for detecting air pollution, a detection means for detecting the output level of this sensor, and a switch for switching the output destination of this detection means. a reference value input means which is one output destination of the switch; a switch switching means which switches the output destination of the switch according to the value inputted by the reference value input means; level adjustment means for adjusting the detection level of the detection means; a comparison value input means which is the other output destination of the switch; and a comparison for taking in signals from the reference value input means and the comparison value input means and comparing the signals. and an output means that outputs an output according to the comparison result of the comparison means, and the reference input means inputs the output of the detection means to the reference value input means, and the output of the detection means is constant. The problem solving means is to adjust and hold the value through the level adjustment means so that the value becomes the same, and then input the output of the detection means to the comparison value input means.

Function: The present invention uses the above-mentioned problem-solving means to create a gas that should become a standard! Adjust the detection level at the resistance value at I change to a certain constant value, use that value as the reference value, and then detect the gas @ pattern from the detected value, and change the output according to this value. be able to.

Embodiment Before giving a detailed explanation of the present invention, the relationship between the gas concentration and the amount of change in the gas sensor resistance value will be described.

If the reference resistance value (clean air) is RO1, the air to be detected, the resistance i'UM is R, and the amount of change in resistance value of air containing inbutane 1o00pPH is 1, then the relationship between each gas concentration and the amount of change in resistance value is The relationship is as shown in FIG. As is clear from this figure, what can be detected by the gas sensor is relative to how much the gas concentration has changed with respect to the gas concentration based on Al. Therefore, no matter how much the reference gas resistance value RO varies, the amount of change in gas concentration can always be derived from the relationship R/RO. Therefore, the resistance value of the gas sensor does not need to be detected as an absolute value, and the entire amount of change in gas concentration can be detected from the amount of change with respect to the reference gas concentration level. As a result, if the detection level at the reference gas concentration can be kept constant, the amount of change in gas concentration can always be detected with the same accuracy.

An embodiment of the present invention will be described below with reference to FIG.

As shown in the figure, the gas sensor 1 inputs to the detection means 2,
This detection means detects the output level of the gas sensor 1.

The switch 3 is for switching the cutting edge of the detection means 2.
The reference value input means 4 is one output destination of this switch 3. The switch switching means 6 switches the output destination of the switch 3 according to the value input by the reference value input means 4.

The level adjustment means 6 is for adjusting the detection level of the detection means 2 according to the value input by the reference value input means 4. The comparison value input means 7 is the northern output destination of the switch 3, and the comparison means 8 receives signals from the reference value input means 4 and the comparison value input means 7 and compares the values. The output means 9 performs an output according to the result of comparison by the comparison means 8.

To explain the operation of the above configuration, first, in order to set the reference resistance housing, the switch 3 is switched to the reference value input means 4 side. Then, the value of the gas sensor 1 input to the reference value input means 4 is sent from the reference value input means 4 to the detection means 2 via the level adjustment means 6 so that it becomes a certain constant value. This process is repeated until the value output from the detection means 2 becomes a constant value. When the reference value input means 4 confirms that this value has become a certain constant value, the reference value input means 4 sends a signal to the level/L/adjustment means 6 to maintain the level adjustment value as it is.
A signal for switching the switch 3 is output to the switch switching means 6. Upon receiving these signals, the reference level of the gas sensor 1 is determined.

In addition, the switch 3 is switched to the comparison value input means 7 side in order to detect the gas concentration. Next, the comparison means 8 compares the reference resistance value RO held by the reference value input means 4 and the resistance value R of the gas sensor 1 taken into the comparative input means 7 this time, and outputs according to the comparison value. The output content of the means 9 is changed.

Next, a second
The above operation will be explained in more detail using figures. The resistance value RO of the gas sensor 1 is divided by the resistance value of the electronic regulator 10 to obtain a partial pressure value. First, in order to set a reference value, the switch 3 is switched to the reference value input means 4 side. If the voltage value input to the reference value input means 4 is high, the resistance value of the electronic volume 1o is decreased, and if the voltage value is low, the resistance value of the electronic volume 10 is increased. It is sent from the reference value input means 4 to the detection means 2 via the level adjustment means 6 so that it becomes a certain constant value. Then, this process is repeated until this voltage value becomes a constant value. When the reference value input means 4 confirms that this electrician value has become a certain constant value, the reference value input means 4 outputs the voltage value to the level adjustment means 6 to maintain the voltage value as it is, and sends a signal to switch the switch 3. Output to means 6. In response to these signals, the reference level of the gas sensor 10 is determined, and the switch 3 is switched to the comparison value input means 7 side in order to detect the gas concentration. Next, the comparison means 8 compares the reference value To (RO) held by the reference value input means 4 and the comparison value V(R) of the gas sensor 1 which is input into the comparison value input means γ this time. The output content of the output means 9 is changed according to the value.

Next, a practical example of the pond according to the present invention will be explained with reference to FIG. Components having the same configuration as those in the above embodiment are given the same reference numerals and explanations will be omitted.

As shown in the figure, threshold voltage setting means 11
is for setting a threshold level. The electric charge output from the DC power supply 12 is stored in the capacitor 13. The switch 14 switches the connection of the gas sensor 1 between the DC power supply 12 and the ground, and is controlled by the control means 16. The counter 16 inputs the voltage value output from the threshold voltage setting means 11 and the charging voltage value of the capacitor 13, and measures the time from when the capacitor 13 starts charging until the charging voltage value becomes larger than the threshold voltage value. is counted at a certain sampling period.

To explain the operation in the above configuration, first, switch 1
4 to the ground side to discharge the charge stored in the capacitor 13. When discharging is finished, the switch 14 is switched to the DC power supply 12 side to start charging. The charging curve at this time depends on icR of the resistance value R of the gas sensor 1 and the capacitance value C of the condenser 13, as shown in FIG. 4(1)). The moment the switch 14 is switched to the DC power supply 12 side, the counter 16 starts counting at the same 7" ring period.The counter 16 continues counting until the charging voltage value rises to the threshold level. From this count value, the Detecting concentration.

Therefore, when the gas concentration changes, the resistance value of the gas sensor 1 changes, and the charging time of the capacitor 13 changes.

As a result, the value counted by the counter 16 also changes, and the amount of change T/T o in the gas 711 degrees can be detected.

At this time, as shown in FIG. 6(b), if the reference resistance values are different, the reference value ■ changes to ■, and if the gas concentration changes to ■, it changes to ■. At this time, by varying the sampling period from 11 to t2 so that the number of counts of charging voltage time at the reference gas concentration is constant T, the amount of change in gas concentration is always constant at T/TQ. Can be detected with precision.

In the above embodiment, the resistance value of the gas sensor 10 is converted into a voltage value or time for detection, but the point is that even if the reference value of the gas sensor 1 varies by about 100 times, the amount of change in gas concentration with respect to the reference gas concentration Any method that can detect with the same accuracy may be used.

Effects of the Invention As is clear from the above embodiments, according to the present invention, the output level at a certain reference resistance value of the gas sensor is kept constant, and the amount of change in gas is detected by detecting the amount of change relative to this value. As a result, the degree of air pollution can always be determined with a constant resolution (for example, 8 bits) regardless of variations in the reference resistance value.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an air purifying layer according to an embodiment of the present invention.
Figure 2 is a block diagram of the air purifier with some specific circuits added, Figure 3 is a block diagram of another embodiment of the present invention, and Figure 4 is a block diagram of the same embodiment of the present invention.
Figures (a) to (C) are operation timing diagrams when the standard resistance value of the air purifier is small, respectively, and Figures 6 (IL) to (
0) is an operation timing diagram when the reference resistance value of the air cleaner is large, and FIG. 6 is a gas concentration-variation characteristic diagram showing the amount of change in resistance of the gas sensor with respect to each gas concentration. 1... Gas sensor (sensor), 2...
detection means, 3... switch, 4... reference value input means, 5... switch switching means,
6... Level adjustment means, 7... Comparison value input means, 8... Comparison means, 9... Output means.

Claims (1)

[Claims] A sensor that detects air pollution, a detection means that detects the output level of this sensor, a switch that switches the output destination of this detection means, a reference value input means that is one of the output destinations of this switch, and this reference value. switch switching means for switching the output destination of the switch according to the value input by the input means; level adjustment means for adjusting the detection level of the detection means according to the value input for the reference value input means; Comparison value input means that is the other output destination, comparison means that receives signals from the reference value input means and comparison value input means and compares the values, and output means that outputs according to the comparison result of the comparison means. The reference value input means adjusts and holds the output of the detection means at a constant value through the level adjustment means while inputting the output of the detection means to the reference value input means, and then An air purifier in which the output of the detection means is input to the comparison value input means.