JPS6351897B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle light control device that enables proper lighting of lights when entering a tunnel.

In addition to being able to turn vehicle headlights on and off manually, it is also being considered to have them automatically turn on and off depending on the surrounding brightness. Figure 1 shows a conventional vehicle light control device that enables such automatic lighting/extinguishing, in which 1 is a light sensor such as a CdS whose resistance value decreases as the illuminance increases, 2
is a dividing resistor, 3 is a comparator, the voltage divided by the optical sensor 1 and the dividing resistor 2 is input to its positive input terminal, and the reference voltage V corresponding to the threshold for turning on and off the light is input to its negative input terminal. _R is entered.
4 and 5 are resistors for giving hysteresis characteristics to the thresholds for turning on and off (for example, turning on at 40 lux and turning off at 90 lux), 6 is a base current limiting resistor, 7 is a relay driving transistor,
8 is a relay for light control, 9 is a light such as a headlamp, and light 9 is when the output of comparator 3 is "H"
It lights up when it is at the (High) level and goes out when it is at the "L" (Low) level.

By the way, in such a vehicle light control device, the threshold for turning on and off is constant, so it will not turn on near the entrance of a relatively bright tunnel, which is often the case these days, and even in tunnels that are not so bright, the area near the entrance will be affected by light from outside. Due to the high illuminance, the lights may not turn on until you are a certain distance into the tunnel. When the surrounding illuminance is low, such as at dusk, there is no problem with driving in such a bright tunnel because the human eye can follow it without turning on the headlights, but when driving in the daytime, the tunnel Even if the illuminance inside the tunnel is the same as at dusk or at night, the human eye cannot follow the tunnel as it suddenly enters the tunnel from the bright outside and it feels very dark to the senses, so it may be difficult to drive without the headlights on.

The present invention was made in view of the above points, and in a light control device that turns on and off headlamps based on the illuminance around the vehicle, in order to accurately turn on and off headlamps when entering a tunnel, it is necessary to The system records illuminance data, compares the current illuminance with the recorded illuminance data, and when the difference in illuminance exceeds a predetermined value, it determines that the vehicle has entered a tunnel and turns on the light. .

The present invention will be explained below based on the drawings.

FIG. 2 shows an embodiment of the light control device according to the present invention, in which 10 is an A/D converter that converts illuminance data input as an analog value into a digital signal, and 11 is n shift registers _SR1. -SR _o , each register having the same bit as the output of the A/D converter 10. 12 is a control unit that inputs vehicle speed pulses and controls A/D conversion and data shifting every fixed number of vehicle speed pulses, that is, every fixed traveling distance; 13a to 12;
13e is a ROM in which digital values corresponding to various illumination levels are written; 13a, 13b, and 13c are used to control the lighting/extinguishment of lights based on tunnel detection; and 13d and 13e are used to control lighting/extinguishing of lights at dusk as in the past. Used to control lights out. 14a~
14e is an arithmetic circuit which outputs an "H" (High) signal when data A, which is input as a digital signal, exceeds data B. 14a, 14b,
14c turns on/off by tunnel detection, 14
d and 14e are used for turning on/off the lights at dusk.
Furthermore, 15 is an inverter, 16 is an AND circuit, 1
7 is R-S flip-flop (set priority), 1
8 is an inverter, which constitutes a light control circuit during tunnel detection; 19 is an inverter; 20 is an R-S flip-flop (set priority); 21 is an inverter; these constitute a light control circuit at dusk. are doing. 22 is an OR circuit which inputs the output of the inverter 18 and the output of the inverter 21 and outputs a write control signal. 6,
7, 8, and 9 are similar to the conventional control circuit shown in FIG. Turn on the light.

Next, the operation of the above control circuit will be explained.

In order to make the explanation easier to understand, the following explanation will be specifically explained using numerical values, but each setting value in the explanation can originally be set freely. There are also head lamps and auxiliary lights (tail lamps, clearance lamps, etc.) as lights that are controlled to turn on/off.
Although each can be controlled by setting a lighting/lighting-off threshold value separately, for the sake of simplicity, a case will be described in which "lights" are controlled all at once.

For example, the lighting threshold at dusk and the lighting threshold at dawn are set to 40 lux and 90 lux, respectively, and the data for those thresholds is stored in ROM ₅ 13e and
Each is written in ROM ₄ 13d.

First, the control unit 12 generates a signal for A/D conversion of illuminance data and data shifting every time a fixed number of vehicle speed pulses are input (ie, the vehicle travels a fixed distance). Upon receiving this signal, the A/D
Converter 10 converts the illuminance data into digital signals. On the other hand, the shift register group 11 first moves the contents of shift register SR _o-1 to shift register SR _o ,
Next, data shifts are performed sequentially such as moving the contents of shift register SR _o-2 to shift register SR _o-1 , and finally, after moving the contents of shift register SR ₁ to shift register SR ₂ , A/D conversion is performed. Transfer the current illuminance data to shift register _SR1 . At this time, the data held in shift register SR _o will be discarded. By shifting the illuminance data in this way, the shift register group 11
The shift register SR _o stores the illuminance data sampled n times before, and the shift register SR ₁ stores the current illuminance data.

Next, light lighting control based on tunnel detection during actual driving will be explained.

First, if you are driving with ambient illuminance of 300 lux or more during the day, the inverter 18 and the inverter 2
Since both 1 and 1 output "L" (Low) level outputs, light 9 does not light up. If the vehicle enters a tunnel from this state, the illuminance outside the vehicle will be less than 150 lux, and data equivalent to 150 lux or less will be written to shift register _SR1 . At this time, the illuminance data sampled n times ago is 300 lux or more, and the input A to the calculation circuits 14a, 14b, 14c is
exceeds input B, so all outputs "H" level. In this state, the output of the AND circuit 16 is "H" and the output of the R-S flip-flop 17 is "L", so the output of the inverter 18 is "H".
Next, light 9 is turned on. After the light 9 is turned on, the output of the R-S flip-flop 17 is maintained until the set input signal goes to the "H" level, that is, the illuminance data of 200 lux or more is written to the shift register _SR1 , and the arithmetic circuit 14b goes to the "L" level. The "L" level is maintained until the output is output, and the light 9 remains lit.

Next, the vehicle escapes from the tunnel and the illuminance outside the vehicle is 250.
If it is more than lux, R-S flip-flop 1
The set input of inverter 7 becomes "H" level, and as a result, the output of Q becomes "H", so the output of inverter 18 becomes "L" level, and light 19 is turned off.

For example, if the timing of A/D conversion and data shift is to be performed every rise (or fall) of the vehicle speed pulse, and if n is 16 and the period of the vehicle speed pulse is 1 pulse/0.78 m, then the illuminance sampled n times before For example, the data will be about 12 meters in front of you, and while driving for 12 meters, it will change from more than 300 lux to 150 lux.
Cases where the lux changes below lux are extremely rare unless there are obstacles such as tunnels or guards, so tunnels can be detected in most cases during the day, and lights can be used even in relatively bright tunnels where it was previously impossible to turn on the lights. Can be lit.

Additionally, 200 lux is set as the threshold for turning off the lights when exiting the tunnel, because the ambient illuminance decreases while driving through the tunnel, and what was over 300 lux before entering the tunnel becomes less than 300 lux when exiting the tunnel, and the lights do not turn off. This is to prevent such situations.

Next, if the ambient illuminance gradually decreases at dusk and the current illuminance data written to shift register SR ₁ becomes less than 150 lux, the light will not turn on because shift register SR _o is less than 300 lux. ROM ₄ 13d and ROM ₅ 13e, arithmetic circuits 14d and 14e, inverter 19, R-S
The flip-flop 20 and inverter 21 perform the same control as in the prior art, in which the light 9 is turned on for the first time when the illuminance decreases to 40 lux or less, and is turned off when it is 90 lux or more.

Since human eyesight can sufficiently follow such gradual illuminance changes, it is appropriate to set the lighting threshold low for entering a tunnel during the daytime as described above.

FIG. 3 shows another embodiment of a light control device according to the invention, in which the same reference numbers as in FIG. 2 indicate the same components.

This embodiment is an example in which a microcomputer (consisting of a CPU and ROM) is used in place of the arithmetic circuit and control circuit in the embodiment shown in FIG. 2, and a RAM is used as a shift register. The contents are almost the same as in Figure 2. FIG. 4 is a flowchart of a program for operating the light control device shown in FIG. 3, and will now be briefly explained with reference to the flowchart of FIG.

An interface circuit 23 that generates a signal to interrupt the interrupt terminal of the control unit 24 at the rise (or fall) of the vehicle speed pulse.
When an interrupt signal is given from , control as shown in the flowchart shown in FIG. 4 is performed. In other words, in FIG.
A/D conversion is performed at 0 (step a), and then this illuminance data is shifted within the RAM 25, that is, the illuminance data in memory n is discarded and the illuminance data in memory (n-1) is transferred to memory n, Memory (n-
The illuminance data of 2) is transferred to memory (n-1), the illuminance data of memory 2 is similarly transferred to memory 1, and the A/D converted illuminance data is written in memory 1 (step b). The control unit 24 determines whether the light is ON or OFF (step c)
After that, if the light is off, proceed to step d. In this flowchart, steps d to g are a program for detecting a tunnel and turning on the light. Only when the same conditions as explained in FIG. 2 are met, it is determined that there is a tunnel and the light is turned on. Here, memory A used in step f
This is to differentiate the lights-off threshold between lighting due to tunnel detection and lighting at dusk even if the same light is turned on. For example, when lighting is detected when a tunnel is detected, "1" is set in memory A, By setting "0" to the time when the light is turned on, it is possible to make a difference in the light-off threshold. Steps k to m are programs for turning on the lights at dusk, steps h to j are programs for turning off the lights when exiting a tunnel, and steps i and j are programs for turning off the lights at dawn, etc.

The control device shown in Fig. 3 and the program shown in Fig. 4 can perform almost the same control as shown in Fig. 2.
Furthermore, in the case of this embodiment using a microcomputer, in addition to the control shown in FIG. 2, the following detailed control can be easily performed. For example, in this embodiment, only the illuminance data sampled n times before and the current illuminance data are used as the illuminance data for tunnel detection.
The detection rate of tunnels can be further increased by setting various conditions to detect tunnels based on the illuminance data that has been captured several times in the past and the current illuminance data. In addition, in this embodiment, the threshold for turning on/off the lights is set to two levels, as in the past, at dusk and dawn, and when entering and exiting a tunnel during the day, but there are also three or more levels of turning on/off due to spatial changes in illuminance. It is possible to set a threshold value (for example, to perform tunnel detection even at dusk). Although not shown in this embodiment, when driving in an urban area at night, there is a delay in turning off the lights in order to prevent the so-called hunting phenomenon in which the lights repeatedly turn on and off due to temporary changes in illuminance due to the light of street lights. If this is provided, an unfavorable situation may occur in which the light does not turn off immediately after exiting the tunnel after being turned on by entering the tunnel. In this embodiment using a microcomputer, this problem can be easily solved because it can be controlled so that the delay in turning off the light varies depending on the lighting mode, that is, whether the light is turned on by tunnel detection or dusk detection.

As explained above, according to the present invention, illuminance data is captured and stored every time a certain distance is traveled,
When there is a sudden change in illuminance between the current illuminance and the illuminance a certain distance before, it is determined that the tunnel has entered, and the light lighting threshold is set higher than the lighting threshold at dusk to create a relatively bright tunnel or tunnel. The light can be turned on even near entrances and exits, which helps human eyesight lag in responding to sudden changes in ambient illuminance, improving safety.In addition, the light can be turned on at the same time as the tunnel enters, improving the feeling. can be significantly improved.

Since the tunnel detection function according to the present invention is based on distance, spatial changes in illumination can be accurately detected regardless of the speed of the vehicle, and the detection rate is significantly higher than the conventional method of detecting changes in illuminance over time. The present invention can be applied not only to the control of lights but also to the volume control of power windows, radios, stereos, etc.

[Brief explanation of the drawing]

Fig. 1 shows an electric circuit of a conventional light control device, Fig. 2 shows an electric circuit of an embodiment of a light control device according to the present invention, and Fig. 3 shows another embodiment of a light control device according to the present invention using a microcomputer. FIG. 4 is a flowchart illustrating the operation of the control device shown in FIG. 3. 1... Optical sensor, 2... Dividing resistor, 3... Comparator, 4, 5... Resistor, 6... Base current limiting resistor, 7... Relay driving transistor, 8... Light control relay, 9 ...Headlamp, 10...
...A/D converter, 11...Shift register group, 1
2... Control section, 13a to 13e...
ROM, 14a-14e... Arithmetic circuit, 15, 1
8, 19, 21...Inverter, 16...AND
Circuit, 17, 20...R-S flip-flop,
22...OR circuit.

Claims (1)

[Claims] 1: an illuminance sensor that detects illuminance outside the vehicle and outputs illuminance data; a storage means that stores the illuminance data while the vehicle travels at least a certain distance; and updates the illuminance data every time the vehicle travels a certain distance; and an output from the illuminance sensor. and a lighting/extinguishing control means that compares illuminance data stored in the storage means with illuminance data stored in the storage means, determines a change in illuminance of a predetermined width or more, and controls turning on or off of the light. Light control device.