JPS6357321A - Automatic control device for automobile air purifier - Google Patents

Abstract

PURPOSE:To appropriately control an air-purifier, by comparing two reference values obtained by dividing a battery voltage, with an intermediate level detected voltage to detect a variation in the battery voltage, and by controlling the air-purifier in accordance with the result of the detection. CONSTITUTION:A battery voltage setting means 21 divides a battery voltage, by means of resistors R1-R4 to set two reference voltages, and an intermediate level detected voltage between the reference voltages. Further, an amplifier 2 amplifies the detected voltage, and a variation detecting means 23 compares thus amplified detected voltage with the reference values to detect a variation in the battery voltage. Further, a smoothing section 24 smoothens the detected voltage from the means 23, and a comparator 25 compares thus smoothened detected voltage with the reference voltages set by the variable resistors. Further, a drive circuit 26 drives an air purifier 17 in accordance with an operational signal from the comparator 25. With this arrangement, even if the battery voltage lowers, the detection of a battery voltage may be stably made, thereby it is possible to control the air-purifier 17 always appropriately.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an automatic control device for an automobile air cleaner using a battery as a driving power source.

[Conventional technology]

FIG. 3 is a circuit diagram showing a conventional automatic control device for an air purifier for an automobile, as disclosed in, for example, Japanese Utility Model Application Publication No. 60-68818, where A is the circuit on the vehicle body side and B is the circuit on the air purifier side. Each circuit is shown.

In the figure, 1 is a 12V line connected to a battery (not shown), 2 is a door switch, 3 is a room lamp, 4 is a switch that controls the ON and OFF of the room lamp 3, and 5.6 is a switch that controls the ON and OFF of the room lamp 3. Resistor to divide battery voltage,
7 is a diode connected between the voltage dividing point and the door switch 2, 8 is a Zener diode provided as a battery voltage detection means, and the voltage dividing point is connected to the transistor 9.
is connected between the base of the 10 is a transistor switched by transistor 9; 11 is a detector for detecting the degree of pollution of the city air;
It operates when it is open or conductive, and outputs a voltage depending on the degree of air pollution. 12 is a comparator that compares the output voltage of the detector 11 with the reference voltage set by the variable resistor 13; 14 is a transistor driven by the output of the comparator 12; 15 is its base resistor; 16 is driven by the transistor 14. relay, whose normally open contact is connected to air purifier 1.
7 is connected in series.

Next, let's talk about the action. A driver gets into a car,
When you operate the key switch (not shown) to start the engine, the battery is charged and its voltage increases to 11~12
．． The voltage rises from 5V to 12.5V to 14.5V. This voltage rise causes the voltage at the voltage dividing point mentioned above to rise, and when it becomes higher than the breakdown voltage of the Zener diode 8, the base current flows through the transistor 9, turning it on, and the transistor 1
0 is also turned on. As a result, the battery voltage is applied to the detector 11 from the 12V line 1, and the detector 11 becomes ready for operation. In this state, if the degree of contamination of the air inside the vehicle is high and exceeds the reference value, the detector 11 detects this and outputs to the comparator 12 an analog voltage corresponding to the degree of contamination. At this time,
The output 'voltage of detector 11 is higher than the reference voltage, and comparator 1
The transistor 14 is supplied with a base current by the output of the transistor 2 and is turned on. This activates the relay 16, closing its contacts, and the air purifier 17 starts operating. Then, when the air inside the car is purified and the output voltage of the detector 11 becomes lower than the reference voltage, the transistor 14 is turned off.
The air cleaner 17 stops. Further, if the engine is stopped while the air purifier 17 is operating, the battery voltage drops to 11 to 12.5V, and the voltage at the F distribution pressure point drops. When the voltage at this voltage dividing point drops below the breakdown voltage of the Zener diode 8, the silane resistor 9 turns off.
Transistor 10 is also turned off. Due to two reasons, detector 1
1 is stopped, and at the same time, the air cleaner 17 is also stopped.

[Problem that the invention seeks to solve]

However, in the above-mentioned automatic control device for an air purifier for an automobile, a Zener diode is provided as a means for detecting battery voltage, and the breakdown voltage of this Zener diode determines whether to operate or stop the air purifier. Therefore, there was a problem that detection of the battery voltage became unstable and the air purifier could not be properly controlled.

In other words, the battery voltage after starting the engine may vary even if the engine is running, if the battery has been used for a long time or if the load is heavy (for example, if the engine is idling and the headlights are on or the air conditioner is on). The voltage may drop to 11 to 12.5V, and in such a state, the Zener diode causes the battery voltage detection means to stop or repeatedly stop and operate, thereby preventing proper control of the air purifier. The problem was that it was not possible to do so.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an automatic control device for an air purifier for an automobile that can always perform appropriate control of the air purifier.

(Means for Solving the Problems) The automatic control O1l device for an automobile air cleaner of the present invention divides the battery voltage to set two reference voltages having different levels, and also sets an intermediate level between the two reference voltages. a battery voltage setting stage for setting the detection voltage of the battery, an amplifier for amplifying the detection voltage, and a fluctuation detection means for detecting fluctuations in the battery voltage by comparing the amplified detection voltage with two reference voltages. , its detection (smoothing part that smoothes No. A, and this smoothed detection signal as reference 13
The air purifier is equipped with a comparator that compares the air purifier with the air purifier, and a drive circuit that drives the air purifier based on the operating signal from the comparator.

(Function) Fluctuations in the battery voltage are detected by comparing the 2nd reference voltage obtained by dividing the battery voltage with the detection voltage at the intermediate level, so the battery voltage can be detected at low peaks while the engine is running. However, the battery voltage is detected stably and the air purifier is controlled to the appropriate IE.

C Example] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

The first L121 is a circuit configuration diagram showing an automatic LT room air cleaner automatic control device according to the present invention. In the figure,
21 divides the battery voltage (+V) using resistors R7 to R4 to set two reference voltages V, , V2 having different levels, and detects a detection voltage (V + >
The detected voltage v3 is a voltage divided by the resistors R, , R6.

Further, the reference voltages V and (2) have a potential difference of several volts, and are difficult to change due to the capacitor C due to battery voltage fluctuations, and the detection voltage v3 is designed to directly transmit the battery voltage fluctuations. 22 is an amplifier for amplifying the detection voltage (3), and 23 is a fluctuation detection means (23) for comparing the detection voltage v4 amplified by the amplifier 22 with the two reference voltages V, , V, respectively, to detect fluctuations in the battery voltage. window comparator), and the comparators 23a and 23b
The output side of is connected via resistors Rt and Ra.

The amplified detection voltage v4 is applied to the non-inverting input terminal f(+) of the comparator 23a and the inverting input terminal Q'f of the comparator 323b.
-(-), and the reference voltage v1 is applied to the comparator 23a
The inverting input terminal (-) of the comparator 23b and the reference voltage v2 are respectively applied to the non-inverting input terminal (+) of the comparator 23b. 24 is a smoothing unit that smoothes the detection voltage v5 which is the output signal of the fluctuation detection means 23; 25 is a comparator that compares the smoothed detection voltage with a reference voltage set by the variable resistor VR; 26 is a component from the comparator 25; This is a drive circuit that drives the air cleaner 17 based on the activation signal.

- In the circuit configuration described in F, the detection voltage V4 amplified by the amplifier 22 is positive (
+) or negative (-). Then, the positive detection voltage v4 becomes higher than the reference voltage V, and at this time, the output of the fluctuation detection means 23 changes from a low level to a high level. Furthermore, the negative detection voltage v4 is the reference voltage v2
At this time, the output of the fluctuation detection means 23 changes from low level to high level. In this way, the fluctuation detection means 23 including the two comparators 23a and 23b is an effective means for detecting a constantly fluctuating voltage such as a battery voltage. The output of the fluctuation detection means 23 becomes a pulse waveform that repeats high and low levels while detecting fluctuations in the battery voltage, and therefore the smoothing section 24
It is smoothed and becomes a DC signal. This signal is then compared with a reference signal by a comparator 25, and if the voltage level is higher than the reference signal, the comparator 25 activates (No. 2 is output), and the drive circuit 26 makes the air cleaner 17 ready for operation.

FIG. 2 is a timing chart showing the operation of the fluctuation detection means 23. As shown in the figure, when the car engine is stopped, there is no change in the battery voltage, and the detected voltage v4 is equal to the reference voltages V and V.

The output of the fluctuation detection means 23 is at a low level and the air cleaner 17 does not operate. Then, during engine operation, fluctuations occur in the battery voltage of the determining means, and the detected voltage (4) changes significantly in positive and negative directions. When this detection voltage V4 becomes higher than the reference voltage V or lower than the reference voltage V2, the output of the fluctuation detection means 23 changes from a low level to a high level, and at this time the air cleaner 17 becomes operational.

In this way, the battery voltage detection means is a fixed voltage (breakdown voltage) such as a Zener diode as in the past.
As described above, the variation in battery voltage is detected by the variation detection means 23 as described above, so even if the battery voltage drops during engine operation, the battery voltage can be detected stably, and the air purifier PJ17 can be controlled properly at all times.

〔Effect of the invention〕

As explained above, according to the present invention, fluctuations in battery voltage are detected by comparing two reference voltages obtained by dividing the battery voltage with a detection voltage at an intermediate level, and based on the detection results, Since the air purifier is controlled, even if the battery voltage drops while the engine is running, the battery voltage can be detected stably, and the air purifier can be controlled appropriately at all times.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention, FIG. 2 is a time chart showing the operation of the fluctuation detection means of FIG. 1,
FIG. 3 is a circuit diagram showing an automatic control device for a conventional air purifier for automobiles. 17...Air purifier 21...Battery voltage setting means 22-...
...Amplifier 23...Fluctuation detection first stage 23a, 23b---Comparator 24---Smoothing section 25...Comparator 26...Drive Circuit 21 Fig. 1 23 Two motion detection hands, 23a, 23b: Hijoon Fig. 2

Claims (1)

[Claims] a battery voltage setting means for dividing a battery voltage to set two reference voltages having different levels and setting a detection voltage at an intermediate level between the two reference voltages; an amplifier for amplifying the detection voltage; fluctuation detection means for detecting fluctuations in battery voltage by comparing the detected voltages with the two reference voltages, a smoothing section for smoothing the detection signal, and a comparator for comparing the smoothed detection signal with the reference signal. 1. An automatic control device for an air purifier for an automobile, comprising: and a drive circuit that drives the air purifier using an operating signal from the comparator.