JP2562443Y2 - Vehicle tunnel detector - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a vehicle tunnel detecting device for detecting passage of a tunnel according to a change in illuminance outside a vehicle.

[0002]

2. Description of the Related Art Recently, when a vehicle passes through a tunnel,
Technologies for automatically controlling various loads on vehicles have been developed.
For example, a technique has been proposed in which a light is automatically turned on when entering a tunnel, a wiper is automatically stopped, or an inside / outside air switching damper of an air conditioner is automatically switched to an inside air circulation side. To detect the passage of a tunnel, Japanese Patent Application Laid-Open No. 60-163744 discloses that an AC amplifier circuit amplifies an AC component of a lighting lamp in a tunnel, while an AC detection circuit detects an AC voltage from the AC amplifier circuit. A technique has been proposed in which a signal is compared with a fixed level reference voltage set by a resistor to detect passage through a tunnel.

[0003]

However, there are various types of light that generate the above-described AC component while the vehicle is running. For example, when a vehicle travels under a street tree or under an overpass in the daytime, sunlight is discontinuously incident on the illuminance sensor, and the above-described AC component is generated. As described in Japanese Patent Application Laid-Open No. SHO 60-163744, when the reference voltage is at a constant level, when the vehicle travels on a street tree, under a bridge, or the like in the daytime, the AC component caused by the illumination light in the tunnel. The generated pseudo AC component could not be clearly distinguished, and it was difficult to accurately detect the passage through the tunnel.

[0004]

SUMMARY OF THE INVENTION The present invention clearly distinguishes an alternating current component caused by a lighting lamp in a tunnel from a pseudo alternating current component generated when a vehicle runs under a street tree or under an overpass in the daytime. The purpose is to accurately detect the passage of a tunnel. In order to achieve the object, a first amplifying unit for amplifying an output signal from the illuminance sensor, a second amplifying unit for amplifying an AC component of the output signal from the illuminance sensor, and the second amplifying unit And a comparator connected to the first amplifier, comparing the output level of the second amplifier with the output signal of the first amplifier as a threshold, and outputting a tunnel detection signal. A tunnel detecting device for a vehicle is provided.

[0005]

1 is an electric circuit diagram showing a preferred embodiment of the present invention, wherein 1 is an illuminance sensor, 2 is a tunnel detection circuit, 3 is a microcomputer, 4 is a light system load,
5 is a wiper system load, and 6 is an air conditioner system load.

First, the illuminance sensor 1 is a sensor that detects the illuminance outside the vehicle and is installed with the light receiving direction facing the outside of the vehicle, and includes a photodiode 1a and an operational amplifier 1b. Also,
The tunnel detection circuit 2 includes a first amplification unit 21 and a second amplification unit 2
2, a comparison unit 23 and an AD conversion unit 24. More specifically, the first amplifying unit 21 amplifies the output signal from the illuminance sensor 1, and includes an operational amplifier 21 a and a capacitor 2.
1b and resistors 21c to 21f. In particular, the circuit including the capacitor 21b and the resistors 21e and 21f divides and smoothes the potential A [V] at the output side of the operational amplifier 21a and derives it to the point B.
[V] is input as a threshold value to the comparison unit 23 in the subsequent stage. The second amplifying unit 22 amplifies the AC component of the output signal from the illuminance sensor 1, and includes operational amplifiers 22a and 22b, a capacitor 22c, and a resistor 22d.
To 22f. The second amplifying unit 22 inputs the potential at point C Vc [V] to the comparing unit 23 in the subsequent stage. Further, the comparing section 23 has a potential Vb [V] at point B and a potential Vc at point C.
[V] is compared, and when the condition of Vb [V] <Vc [V] is satisfied, the potential D at point Dd [V] is set to a high potential, and a tunnel detection signal is output.

The tunnel detection circuit 2 is connected to the microcomputer 3 and outputs an illuminance signal from the A / D conversion unit 24.
Each of the tunnel detection signals is input from the comparison unit 23. The microcomputer 3 receives the illuminance signal and the tunnel detection signal and receives a light load 4 and a wiper load 5.
And, it is programmed to control the air conditioner system load 6. For example, the microcomputer 3 receives an illuminance signal or a tunnel detection signal when the illuminance outside the vehicle has become low, and controls the lighting of the light system load 4 in response to the tunnel detection signal, and controls the stop of the wiper system load 5 in response to the tunnel detection signal. It has a program and a program for switching and controlling an inside / outside air switching damper (not shown) of the air conditioner system load 6 to the inside air circulation side.

Next, the operation of the above embodiment will be described with reference to a time chart shown in FIG. 2A shows the potential Va [V] in FIG. 1A, FIG. 2B shows the potential Vb [V] and the potential Cc V in FIG. 1B, and FIG. 2C shows the potential V in FIG. V
The vertical axis indicates d [V], and the horizontal axis indicates time t [seconds].

(I) Outdoor running in daytime The time period from t1 to t2 [sec] in FIG. 2 illustrates a case where the vehicle runs outdoors in the daytime. At this time, the illuminance sensor 1 is receiving bright light due to sunlight and has a potential Va at the point A.
[V] and B point potential Vb [V] are both high potentials.
When a vehicle travels outdoors in the daytime, an AC component is generated at point C due to a shadow of an overpass, a tree, a building, or the like. However, the point B potential Vb [V], which is a threshold value for tunnel detection, has a high potential as described above due to high illuminance outside the vehicle, and the comparison unit 23 does not output a tunnel detection signal by mistake.

(II) At the time of entry into a tunnel The time from t2 to t4 [sec] in FIG. 2 illustrates the time when a vehicle enters a tunnel. At this time, the illuminance sensor 1 gradually reduces the amount of received light, and the potential at point A Va [V] and the potential at point B V
b [V] also gradually decreases from the high potential to the low potential. As the vehicle enters the tunnel, the illuminance sensor 1 receives light from an illumination lamp in the tunnel. The light of the illumination lamp in the tunnel contains, for example, an AC component of about 100 [Hz] or about 120 [Hz]. Therefore, the AC component generated at the point C becomes remarkable as the tunnel enters, and finally the time t3
In [sec], the potential at point B Vb [V] <the potential at point C Vc
The condition [V] is satisfied, and the potential Vd [V] at the point D becomes high. That is, the comparison unit 23 of the tunnel detection circuit 2
A tunnel detection signal is input to the microcomputer 3.

(III) Running in Tunnel The time after the time t4 [sec] in FIG. 2 illustrates the time when the vehicle runs in the tunnel. At this time, the illuminance sensor 1 receives the light of the illumination lamp in the tunnel, and synchronizes with the cycle of the AC component by the illumination lamp, and the potential at point B Vb [V] <the potential at point C V
The condition of c [V] is satisfied, and the comparison unit 23 of the tunnel detection circuit 2 continuously inputs a tunnel detection signal to the microcomputer 3.

[0012]

[Effect of the Invention] Since the present invention has the above-described configuration and operation, the AC component caused by the illumination light in the tunnel and the pseudo vehicle generated when the vehicle travels under the overpass or under a tree in the daytime. It is possible to clearly distinguish the AC component from the AC component, so that it is possible to accurately detect the entry and the passage of the vehicle into the tunnel. Since the technical object of the present invention can be achieved by varying the degree, it has an excellent effect that the configuration is extremely simple.

[Brief description of the drawings]

FIG. 1 is an electrical circuit diagram showing a preferred embodiment of the present invention.

FIGS. 2A and 2B are time charts showing potential waveforms at respective points in the circuit shown in FIG. 1, wherein FIG.
(B) is a potential at point B Vb [V] and a potential at point C Vc [V],
(C) shows the potential at point D Vd [V].

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Illumination sensor 2 Tunnel detection circuit 21 First amplifier 22 Second amplifier 23 Comparison unit

Claims (1)

(57) [Scope of request for utility model registration] A first amplifying section for amplifying an output signal from an illuminance sensor, wherein the first amplifying section amplifies an output signal from the illuminance sensor; A second amplifying unit for amplifying an alternating current component within, and connecting to the second amplifying unit and the first amplifying unit,
A comparison unit that compares the output level of the second amplification unit with the output signal of the first amplification unit as a threshold value and outputs a tunnel detection signal.