JP2006131048A - Vehicular headlight lighting control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular headlight lighting control device capable of improving flexibility of its installation position, suppressing generation of electromagnetic noise and keeping the illuminance for each headlight constant. <P>SOLUTION: This vehicular headlight lighting control device includes a duty ratio control part 63, semiconductor relays 8, 9 in corporation with the duty ratio control part 63 and a PWM controller for controlling energizing periods from a battery B for respective headlights 1, 2. Duty ratio information is read out by referring to a battery voltage from a memory 61 of which the duty ratio information is stored based on an illuminance command in response to the battery voltage. PWM control is performed by the PWM controller so as to avoid overlapping energizing periods of the headlights 1, 2 in accordance with a duty ratio which is fixed based on the read duty ratio information, and the illuminance of each headlight is detected by each of photo diodes 12, 22. Accordingly, the duty ratio is controlled by the PWM controller so that both detection illuminance may become the same at lower detection illuminance. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle headlight lighting control device.

Conventionally, as shown in FIG. 9, left and right headlights 201 and 202 are arranged in parallel as a vehicle headlight lighting control device capable of controlling a large current load while suppressing electromagnetic noise radiation accompanying flashing of a vehicle headlight. The headlights 201 and 202 connected in parallel are controlled by the PWM control circuit 200. In this case, the energization waveform of the PWM control is formed in a trapezoidal shape, and the headlight blinking control is performed with the trapezoidal energization waveform. It is known to drive the headlight drive element such as a MOS transistor to moderate the change in the current flow of the headlight, thereby reducing electromagnetic noise and controlling a large current load based on the headlight drive. (See, for example, Patent Document 1).
JP-A-9-204230

  However, the prior art of the vehicle headlight lighting control device as described in Patent Document 1 described above performs PWM control on the left and right headlights connected in parallel by one PWM control circuit. For this reason, depending on the installation position of the PWM control circuit, the length of the wire harness from the position of the PWM control circuit to the headlight position on one side and the position from the position of the PWM control circuit to the headlight position on the other side There may be differences in the length of the wire harness. However, in the vehicle, it is desired that the illuminances of the left and right headlights are the same.

  For this reason, it is necessary to make the length of the wire harness the same, and in order to make the length of the wire harness the same, it is said that an extra length is required for the wire harness such as sagging the wire harness on one side There is a problem. On the contrary, when the length of the wire harness is made the same for the left and right headlights without sagging, there is a problem that the degree of freedom of the installation position of the PWM control circuit as the headlight drive source is lost.

  The present invention is for a vehicle in which the degree of freedom of the installation position of the control device that controls lighting of the headlights is improved, the generation of electromagnetic noise is suppressed, and the illuminance for each headlight is constant and high merchandise can be obtained. An object of the present invention is to provide a headlight lighting control device.

  The vehicle headlight lighting control device according to claim 1 of the present invention is provided with PWM control means for controlling the energization period from the battery for each of the left and right headlights, and when lighting instructions for the left and right headlights are given. , Illuminance based on lighting for each headlight by PWM control is detected, and the detected illuminance of the headlight having the higher detected illuminance matches the detected illuminance of the lower side based on the illuminance detection result of the headlight having the lower detected illuminance Thus, the duty ratio in the PWM control means of the side headlight with high detected illuminance is controlled.

  According to a second aspect of the present invention, there is provided the vehicle headlight lighting control device, wherein the left and right headlights are provided with PWM control means for controlling the energization period from the battery, and the left and right headlights are instructed to be dimmed. And control the duty ratio in the PWM control means to reduce the light, detect the illuminance based on lighting of each headlight at the time of dimming, and detect the illuminance on the side where the detected illuminance is low The side where the detected illuminance is high The duty ratio in the PWM control means of the headlight with high detection illuminance is controlled so that the detection illuminance of the headlight matches the detection illuminance on the low side.

  A vehicle headlight lighting control device according to a third aspect of the present invention is the vehicle headlight lighting control device according to the first or second aspect, wherein the energization period in the PWM control of one headlight and the other headlight are controlled. Control is performed so as not to overlap in time with the energization period in PWM control.

  A vehicle headlight lighting control device according to a fourth aspect of the present invention is the vehicle headlight lighting control device according to the first or second aspect, wherein the duty ratio information based on the illuminance target value is stored corresponding to the battery voltage. The duty ratio information is read out from the memory means with reference to the battery voltage, and energization control is performed at the duty ratio in the PWM control means determined by the read duty ratio information.

  According to the vehicle headlight lighting control device of the first aspect of the present invention, the PWM control means for controlling the energization period from the battery is provided for each of the left and right headlights, and the left and right headlights are lit. When instructed, the illuminance based on the lighting of each headlight by PWM control is detected, and the detected illuminance of the headlight having the higher detected illuminance is based on the illuminance detection result of the headlight having the lower detected illuminance. The duty ratio in the PWM control means of the headlight having a high detected illuminance is controlled so as to coincide with the detected illuminance.

  Here, since the PWM control means is provided for each of the left and right headlights, the length of the wire harness connecting the PWM control means and the headlight is the same regardless of the installation position of the PWM control means. The illuminance of the right and left headlights is controlled to the same illuminance as the low detection illuminance. As a result, even if there are restrictions on the design and layout due to external factors such as safety at the time of collision, and internal factors that disturb the engine and accessories, the vehicle can be moved to the desired position by avoiding these restrictions. The headlight lighting control device for a vehicle can be installed, and the degree of freedom of the installation position of the vehicle headlight lighting control device is improved.

  According to the vehicle headlight lighting control device of the second aspect of the present invention, the PWM control means for controlling the energization period from the battery for each of the left and right headlights is provided, and the dimming instruction for the left and right headlights is provided. As a result, the duty ratio in the PWM control means is controlled and dimmed. The illuminance for each headlight at the time of dimming is detected so that the detected illuminance of the side headlight with high detected illuminance matches the detected illuminance on the low side based on the illuminance detection result of the side headlight with low detected illuminance The duty ratio in the PWM control means of the side headlight with high detected illuminance is controlled.

  Thus, since the PWM control means is provided for each of the left and right headlights, the length of the wire harness connecting the PWM control means and the headlight is the same as the PWM control means regardless of the installation position of the PWM control means. The minimum length between the headlight and the headlight is sufficient, and the illuminance of the left and right headlights is controlled to the same detected illuminance as the low detected illuminance even during dimming control. As a result, even if there are restrictions on the design and layout due to external factors such as safety at the time of collision, and internal factors that disturb the engine and accessories, the vehicle can be moved to the desired position by avoiding these restrictions. The headlight lighting control device for a vehicle can be installed, and the degree of freedom of the installation position of the vehicle headlight lighting control device is improved.

  According to the vehicle headlight lighting control device of the third aspect of the present invention, the energization period in the PWM control of one headlight and the energization period in the PWM control of the other headlight do not overlap in time. Therefore, the inrush current during energization and energization cut-off is small, and electromagnetic noise is reduced. As a result, the influence of electromagnetic noise on other electronic devices mounted on the vehicle can be reduced, and the incidental costs related to the problem of resistance to electromagnetic noise can be reduced.

  According to the vehicle headlight lighting control device of the fourth aspect of the present invention, the duty ratio information based on the illuminance target value corresponding to the battery voltage is stored in the memory means, and the memory is referred to the battery voltage. Duty ratio information is read from the means, and energization control is performed at the duty ratio of the PWM control means determined by the read duty ratio information.

  Therefore, according to the vehicle headlight lighting control device of the fourth aspect of the present invention, energization based on the duty ratio corresponding to the battery voltage even when the battery voltage gradually changes due to aging of the battery or the like. Control can be made to follow changes in battery voltage. In the energization control in the PWM control means, when the detected illuminance of the headlight is different, the detected illuminance of the headlight having the higher detected illuminance is matched with the detected illuminance of the headlight having the lower detected illuminance. The duty ratio of the headlight on the higher illuminance side is controlled so that the illuminance of the left and right headlights is the same.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a vehicle headlight lighting control device according to the present invention will be described with reference to embodiments.

  FIG. 1 is a block diagram for explaining the configuration of a vehicle headlight lighting control apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, a vehicle headlight lighting control device 100 according to an embodiment of the present invention receives an output from a combination switch 3 and outputs PWM control signals to the left headlight 1 and the right headlight 2 separately. The microcomputer 4 that outputs, the semiconductor relay 8 that controls the blinking of the left headlight 1 by receiving the PWM control signal output from the microcomputer 4, and the right headlight 2 that receives the PWM control signal output from the microcomputer 4 And a semiconductor relay 9 for controlling the blinking of.

  The combination switch 3 is instructed to turn on a headlight, a DRL switch 32 that instructs to turn on a daytime running light (also referred to as DRL), and a small light that is a vehicle width light. A small light switch 33 and a fog light switch 34 for instructing to turn on the fog light.

  The microcomputer 4 receives the lighting instruction signal from the combination switch 3 via the diodes 41, 42, 43, 44, 45 and receives the output from the combination switch 3 received via the input circuit 5. A CPU 6 that sends out a PWM control signal and an output circuit 7 that converts the PWM control signal output from the CPU 6 to a level for driving the semiconductor relays 8 and 9 are provided.

  The CPU 6 stores the duty ratio information based on the illuminance target value at the time of lighting the headlight corresponding to the battery voltage B, and the duty ratio information based on the illuminance target value at the time of DRL lighting corresponding to the battery voltage B. The stored memory 62 and a duty ratio control unit for sending a PWM control signal for controlling the blinking of the left headlight 1 with a duty ratio based on the duty ratio information read from the memory 61 or 62 with reference to the battery voltage B, that is, PWM control 63 and a duty ratio control unit 64 that sends a PWM control signal for controlling the blinking of the right headlight 2 at a duty ratio based on the duty ratio information read from the memory 61 or 62 with reference to the battery voltage B, that is, PWM control. Is prepared.

  Here, the duty ratio information read from the memory 61 is used when the headlight is lit, and the duty ratio information read from the memory 62 is used when the DRL is lit. Reference numerals 11 and 21 denote headlight element bodies. The headlights 1 and 2 are turned on by energizing the headlight element bodies 11 and 21, but are also simply referred to as headlight lighting.

  The duty ratio control unit 63 and the duty ratio control unit 64 are based on the energization period based on the duty ratio in the PWM control signal output from the duty ratio control unit 63 and the duty ratio in the PWM control signal output from the duty ratio control unit 64. The duty ratio control unit 63 is controlled so as not to overlap with the energization period in time, and the duty ratio control unit 63 is provided in the left headlight 1 to detect illuminance based on lighting of the left headlight element body 11. The duty ratio control unit 64 receives the illuminance detection signal from the photodiode 22 that is provided in the right headlight 2 and detects the illuminance based on the lighting of the right headlight element body 21 and detects the illuminance detection signal. So that the detected illuminance matches the detected illuminance. , I.e. so that both detection illuminance is equal, the larger the intensity, controls the duty ratio in the PWM control signal.

  Here, the illuminance detection signals from the photodiodes 12 and 22 are calculated as the detected illuminance by calculating the average value of the PWM control signal every predetermined number of cycles in the microcomputer 4. This is to compensate for the non-detection period of illuminance in the non-conduction period of the duty ratio.

  As shown in FIG. 2, the semiconductor relay 8 includes a logic circuit 81, a charge pump 82, a MOSFET 83, a current detection circuit 84, and a temperature sensor 85, and the left headlight drive output from the microcomputer 4 via the output circuit 7. Is received by the logic circuit 81, sent to the charge pump 82, converted to a voltage level for driving the MOSFET 83 by the charge pump 82, applied to the gate of the MOSFET 83, and applied to the MOSFET 83. The left headlight 1 is controlled to be turned on.

  A part of the drive current of the left headlight 1 is detected by being shunted to the current detection circuit 84, converted into a voltage by a resistor 86 and sent to the microcomputer 4 to detect disconnection of the left headlight element body 11. . On the other hand, when the temperature of the semiconductor relay 8 is detected by the temperature sensor 85, and when the disconnection of the left headlight element body 11 is detected by the current detected by the current detection circuit 84, when the detected current value is detected as an abnormal value, When the temperature sensor 85 detects an abnormal temperature, the output from the logic circuit 81 to the charge pump 82 is cut off, and the energization to the left headlight 1 is cut off.

  The semiconductor relay 9 is configured in the same manner as the semiconductor relay 8 and controls the lighting of the right headlight 2.

  Here, the microcomputer 4, basically the memories 61 and 62, the duty ratio control unit 63, and the semiconductor relay 8 constitute PWM control means for controlling the lighting drive of the left headlight 1. Further, the memories 61 and 62, the duty ratio control unit 64, and the semiconductor relay 9 constitute PWM control means for controlling the lighting drive of the right headlight 2.

  FIG. 3 is a diagram schematically showing a PWM control portion in the vehicle headlight lighting control device 100 shown in FIG. 2 in a simplified manner.

  In the vehicle headlight lighting control device 100 configured as described above, when the combination switch 3 is operated and the headlight switch 31 is turned on, the lighting instructions of the left and right headlights 1 and 2 are given. The left headlight 1 is subjected to PWM control as shown in FIG. 4A, and the right headlight 2 is subjected to PWM control as shown in FIG. 4B. The duty ratio by PWM control in FIG. 4 is schematically shown.

  More specifically, when the headlight lighting instruction is given, the battery voltage is referred to, the duty ratio information based on the illuminance target value is read from the memory 61, and the duty ratio information shown in FIG. The left headlight 1 is PWM controlled under the control of the duty ratio control unit 63 with the duty ratio shown in a). Similarly, the battery voltage is referred to, the duty ratio information based on the illuminance target value is read out from the memory 61, and the duty ratio control unit with the duty ratio shown in FIG. 5B based on the read duty ratio information. Under the control of 64, the right headlight 2 is PWM controlled so that the energization period and the energization period of the left headlight 1 do not overlap in time.

  Thus, since the PWM control is performed independently for each of the left and right headlights 1 and 2, the degree of freedom of the installation positions of the microcomputer 4 and the semiconductor relays 8 and 9 is improved. The length of the wire harness connecting the semiconductor relays 8 and 9 and the headlights 1 and 2 can be minimized.

  Further, as described above, when the headlight lighting instruction is given, the duty ratio information is read based on the battery voltage, and PWM control is performed based on the duty ratio based on the duty ratio information. It can also cope with it. Furthermore, the inrush current during energization and non-energization of the duty ratio by PWM control is small, and the electromagnetic noise level generated when the energization overlaps (see the broken line frequency vs. noise level A in FIG. 6). In comparison with FIG. 6, the electromagnetic noise level generated when the PWM control is performed so that the energized times do not overlap is suppressed (see FIG. 6B showing the frequency vs. noise level of the solid line). Therefore, the influence of electromagnetic noise on other electronic devices mounted on the vehicle is reduced, and incidental costs related to the problem of resistance to electromagnetic noise can be reduced.

  In this case, the illuminance due to the lighting of the left headlight 1 is detected by the photodiode 12, and the illuminance due to the lighting of the right headlight 2 is detected by the photodiode 22. So that the detected light illuminances of the left and right headlights 1 and 2 are controlled to be equal. As a result, the detected illuminance of the left headlight 1 and the detected illuminance of the right headlight 2 during lighting are controlled to be equal.

  Further, in the vehicle headlight lighting control device 100 configured as described above, when the combination switch 3 is operated and the DRL switch 32 is turned on, the headlight DRL lighting instruction is given, for example, the left side As shown in FIG. 7A, the headlight 1 is subjected to PWM control with a duty ratio with a short energization period, and the left headlight 1 is DRL-lit. As shown in FIG. 7B, the right headlight 2 has a duty ratio with a short energization period, and PWM control is performed so that the energization period of the left headlight 1 and the energization period of the right headlight 2 do not overlap each other in time. The right headlight 2 is DRL lit.

  To further explain this point, when the DRL lighting instruction is given, the battery voltage is referred to, the duty ratio information based on the illuminance target value is read from the memory 62, and the diagram based on the read duty ratio information. The left headlight 1 is PWM-controlled under the control of the duty ratio control unit 63 with the duty ratio shown in FIG. Similarly, the battery voltage is referred to, the duty ratio information based on the illuminance target value is read out from the memory 62, and the duty ratio control unit with the duty ratio shown in FIG. 7B based on the read duty ratio information. Under the control of 64, the right headlight 2 is PWM-controlled and DRL is lit so that the energization period and the energization period of the left headlight 1 do not overlap in time.

  In this case, the illuminance due to the DRL lighting of the left headlight 1 is detected by the photodiode 12, and the illuminance due to the DRL lighting of the right headlight 2 is detected by the photodiode 22. The duty ratio on the headlight side with the higher detected illuminance is adjusted and controlled so that the detected illuminance matches, and the detected illuminances of the left and right headlights 1 and 2 are controlled equally. As a result, the detected illuminance at the time of DRL lighting of the left and right headlights 1 and 2 is controlled equally.

  Thus, since PWM control for DRL lighting is also performed independently for each of the left and right headlights 1 and 2, the degree of freedom of the installation positions of the microcomputer 4 and the semiconductor relays 8 and 9 is improved. The length of the wire harness connecting the microcomputer 4 and the semiconductor relays 8 and 9 and the headlights 1 and 2 can be minimized.

  Thus, since duty ratio information is read based on the battery voltage and PWM control is performed based on the duty ratio based on the duty ratio information, it is possible to cope with aging of the battery. Furthermore, the inrush current during energization and non-energization of the duty ratio by PWM control is small, and the electromagnetic noise generated because the energization timing does not overlap with the electromagnetic noise level that occurs when the energization overlaps. The level is suppressed. Therefore, the influence of electromagnetic noise on other electronic devices mounted on the vehicle is reduced, and incidental costs related to the problem of resistance to electromagnetic noise can be reduced.

  Further, in the PWM control, instead of FIGS. 5 (a) and 5 (b) and FIGS. 7 (a) and 7 (b), the levels of the energization current to the left headlight 1 and the right headlight 2 are respectively shown in FIG. 8 (a). And as shown in (b), by setting the stored contents of the memories 61 and 62 so as to sequentially decrease during the energization period in the PWM control, the current levels flowing in the left and right headlights 1 and 2 are sequentially decreased. . In this case, the illuminances of the left and right headlights 1 and 2 are also controlled to be the same. FIG. 8C shows the combined currents to the left headlight 1 and right headlight 2.

It is a block diagram which shows the structure of the vehicle headlight lighting control apparatus concerning embodiment of this invention. It is a block diagram which shows the structure of the semiconductor relay in the vehicle headlight lighting control apparatus concerning embodiment of this invention. It is the block which simplified and showed typically the PWM control part in the headlight lighting control device for vehicles concerning an embodiment of the invention. It is a wave form diagram with which it uses for description of the energization period and the non-energization period by PWM control in the vehicle headlight lighting control apparatus concerning embodiment of this invention. It is a wave form diagram with which it uses for description of the energization period and the non-energization period by PWM control in the vehicle headlight lighting control apparatus concerning embodiment of this invention. It is a schematic diagram which illustrates the electromagnetic noise level which generate | occur | produces in the case of the PWM control in the vehicle headlight lighting control apparatus concerning embodiment of this invention. It is a wave form diagram with which it uses for description of the energization period and the non-energization period by PWM control in the vehicle headlight lighting control apparatus concerning embodiment of this invention. It is a wave form diagram with which it uses for description of the energization period and the non-energization period by PWM control in the vehicle headlight lighting control apparatus concerning embodiment of this invention. It is explanatory drawing of the conventional vehicle headlight lighting control apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Left headlight 2 ... Right headlight 3 ... Combination switch 4 ... Microcomputer 5 ... Input circuit 6 ... CPU
DESCRIPTION OF SYMBOLS 7 ... Output circuit 8, 9 ... Semiconductor relay 12, 22 ... Photodiode 61, 62 ... Memory 63, 64 ... Duty ratio control part 100 ... Vehicle headlight lighting control apparatus

Claims (4)

  PWM control means for controlling the energization period from the battery is provided for each of the left and right headlights. When the left and right headlights are instructed to light, the illuminance based on the lighting of each headlight by PWM control is detected, and the detected illuminance Based on the illuminance detection result of the low-side headlight, the duty ratio in the PWM control means of the high-side illuminant headlight is controlled so that the detected illuminance of the high-side illuminant headlight matches the low-side detected illuminance A vehicle headlight lighting control device.   For each of the left and right headlights, there is provided PWM control means for controlling the energization period from the battery. When a dimming instruction is given to the left and right headlights, the duty ratio in the PWM control means is controlled to diminish the light. Illuminance based on lighting of each headlight is detected, and based on the illuminance detection result of the headlight with low detected illuminance, the detected illuminance of the headlight with high detected illuminance is detected to match the detected illuminance on the low side A vehicle headlight lighting control device for controlling a duty ratio in PWM control means of a headlight with high illuminance.   The vehicle headlight lighting control device according to claim 1 or 2, wherein the energization period in the PWM control of one headlight and the energization period in the PWM control of the other headlight are controlled so as not to overlap in time. A vehicle headlight lighting control device. 3. The vehicle headlight lighting control device according to claim 1 or 2, further comprising memory means for storing duty ratio information based on an illuminance target value corresponding to the battery voltage, wherein the duty from the memory means is referred to the battery voltage. A vehicle headlight lighting control device that reads out ratio information and performs energization control at a duty ratio in PWM control means determined by the read duty ratio information.

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