JPH05112122A - Automotive air purifier - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an in-vehicle air purifier that shortens the gas sensor stabilization time and enables operation by the gas sensor in a short time. [Constitution] The control circuit 3 controls the rotation of the motor 4, and the gas sensor 5 comprises a sensor section 6 and a heater 7.
A first power supply 8 and a second power supply 9 for supplying a voltage to the second power supply 8 are provided, and the second power supply 9 is set higher than the first power supply 8. The power source selection circuit 10 for switching the power source of the heater 7 is
The second power supply 9 is selected when the power switch 2 is turned on, and after a short time of several seconds to several tens of seconds, the first power supply 8 is selected and output. The sensor detection circuit 11 detects a change in the voltage of the detection resistor 12 to detect a change in the output of the sensor unit 6, and sends a signal to the control circuit 3 to control the rotation of the motor 4. [Effect] By switching the power supply of the heater 7 by the power supply selection circuit 10, the resistance stabilization time of the sensor unit 6 can be shortened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air purifier equipped with a gas sensor.

[0002]

2. Description of the Related Art A conventional on-vehicle air purifier has a gas sensor (about 2
The output of the gas sensor was detected. And
The fan motor was automatically operated when the gas sensor detected gas.

[0003]

However, in the above-mentioned conventional configuration, the fan motor does not operate even if a cigarette is smoked for about 2 minutes after the power is turned on, and if the cigarette is smoked during that time, the resistance value of the gas sensor is reduced. Since it is stable in a dirty state, there is a drawback that it is difficult for the gas sensor to detect even if the user again smokes immediately after that.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide an on-vehicle air purifier in which the gas sensor can be detected in a short time after operation by shortening the stabilization time of the gas sensor.

[0005]

In order to achieve the above object, the present invention provides a gas sensor having a sensor portion for detecting gas components and exhaust gas contained in cigarettes and a heater, and a voltage to the gas sensor. A first power supply and a second power supply having a higher voltage than the first power supply are provided, and the power supply of the heater is switched from the second power supply to the first power supply after a certain time has passed after the gas sensor is energized. A power supply selection circuit is provided, and a resistance value monitoring circuit that detects a change in the resistance value of the gas sensor and inputs it to the power supply selection circuit to switch the heater power supply is provided.

[0006]

In the above structure, since the power source selection circuit switches from the second power source having a high voltage to the first power source after a fixed time has passed after the gas sensor is energized, and the resistance value monitoring circuit monitors the resistance of the gas sensor. , Even if you smoke a cigarette right after you get in the car, you can detect it accurately.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In the figure, 1 is a battery for a power source mounted on an automobile, 2 is a power switch for the battery, 3 is a control circuit for controlling the rotation of a motor 4 for a blower, 5 is a gas sensor including a sensor unit 6 and a heater 7, 8
Reference numerals 9 and 10 denote a first power source and a second power source for supplying a voltage to the gas sensor 5, respectively.
Is set high. Reference numeral 10 is a power supply selection circuit for switching the power supply of the heater 7. This is when the second power supply 9 is selected when the power switch 2 is turned on, and after a short time of several seconds to several tens of seconds. , The first power source 8 is switched and output, and can be easily configured by a timer circuit, an analog switch and the like. Reference numeral 11 denotes a sensor detection circuit, which detects a voltage change of the detection resistor 12 to detect an output change of the sensor unit 6 and sends a signal to the control circuit 3 to control the rotation of the motor 4. The gas sensor 5 promotes the reaction of the sensor unit 6 by the heat generated by the heater 7. The operating principle of the gas sensor 5 is that when smoke or exhaust gas of the detection object touches the sensor unit 6, a chemical reaction occurs. The resistance value of the sensor unit 6 changes. In order to stabilize the resistance value of the sensor unit 6, it is generally known that it is sufficient to increase the heat generation amount of the heater 7 in a short time.

To explain the operation in the above-mentioned configuration, when the power switch 2 is closed and the circuit is energized, the heater 7 of the gas sensor 5 initially receives the second power source 9 selected by the power source selecting circuit 10. Voltage is being applied. Since this voltage is high, the heat generated by the heater 7 becomes large, so that the resistance value of the sensor section 6 rapidly stabilizes. Here, after a few seconds, the supply voltage of the heater 7 is switched to the first power supply 8 by the power supply selection circuit 10, so that the gas sensor 5 can be automatically operated at this point. In this way, by switching the seven power sources of the heater of the gas sensor 5 by the power source selection circuit 10, the resistance stabilization time of the sensor unit 6 can be shortened.

FIG. 2 shows another embodiment. The difference from the above-mentioned embodiment is that a resistance value monitoring circuit 13 is provided and the resistance value monitoring circuit 13 constantly monitors the resistance value of the sensor section 6. After the resistance value reaches a stable value, the power supply selection circuit 1
The power source is switched to the first power source 8 according to 0. With this configuration, the switching timing of the power supply selection circuit 10 can be obtained more accurately than in the above-described embodiment.

[0010]

As is apparent from the above-described embodiments, the vehicle-mounted air purifier of the present invention has a gas sensor having a sensor unit for detecting gas components and exhaust gas contained in cigarettes and a heater, and a voltage applied to the gas sensor. And a second power supply having a higher voltage than the first power supply, and the heater power is supplied from the second power supply to the first power supply after a certain time has passed after the gas sensor is energized. A power supply selection circuit for switching to a power supply is provided. With this configuration, the gas sensor can be operated in a short time by shortening the stabilization time of the gas sensor, thus improving the usability.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of an in-vehicle air cleaner according to an embodiment of the present invention.

FIG. 2 is a circuit block diagram of an in-vehicle air purifier according to another embodiment.

[Explanation of symbols]

 5 Gas Sensor 6 Sensor Section 7 Heater 8 First Power Supply 9 Second Power Supply 10 Power Supply Selection Circuit

Claims (2)

[Claims] 1. A gas sensor having a sensor unit for detecting gas components and exhaust gas contained in cigarettes and a heater, a first power supply for supplying a voltage to the gas sensor, and a voltage higher than the first power supply. An in-vehicle air purifier comprising a second power supply and a power supply selection circuit for switching the power supply of the heater from the second power supply to the first power supply after a lapse of a certain time after the gas sensor is energized. 2. The on-vehicle air purifier according to claim 1, further comprising a resistance value monitoring circuit which detects a resistance value change of the gas sensor and inputs it to a power supply selection circuit to switch the power supply of the heater.