JP2014076726A - Headlight control device for electric automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a headlight control device for an electric automobile with improvement in saving power consumption of a battery to realize an energy-saving travel by applying automatic dimming control to brightness of a headlight responsively to the brightness of a travelling road and the travel condition of a vehicle.SOLUTION: A headlight control device for an electric automobile traveling using a battery 2 as a power source, includes: a light sensor 5 for detecting a brightness condition of a road in travel; an optical sensor such as an on-vehicle camera 6; a control unit 4 for generating a brightness information signal on the basis of information obtained by the optical sensor; and a headlight control circuit 3 for applying dimming control to brightness of a headlight 1 responsively to the brightness information signal, so as to apply dimming control to the brightness of the headlight 1 responsively to the brightness of the travelling road in real time. Additionally, automatic dimming-control is applied to the headlight in a slow driving condition on the basis of congestion information of the road obtained by a navigation 7.

Description

  The present invention relates to a headlight control device for an electric vehicle that runs using a battery as a power source, and automatically adjusts the headlight according to the road on which the vehicle is running, the brightness of the surroundings, and the running state of the vehicle to consume battery power. The present invention relates to a control method that reduces the above.

  Nowadays, with regard to automobile headlight control technology, headlights are turned on and off automatically according to the driving conditions of the vehicle and the surrounding environmental conditions, or when an oncoming vehicle approaches during high-speed driving Various intelligent control methods such as automatic switching from low beam to low beam have been proposed. As an example, the brake state of the vehicle, the status of signal lights installed on the running road, the surrounding environment, the tunnel, or at night Patent Document 1 is known as a headlight control device that has a detection function for automatically turning on and off a headlight according to detection of each state.

JP 2010-111146 A

  By the way, in the above-mentioned patent document 1, the state of the brake of the vehicle and the state of the signal light are detected, it is determined whether the signal is stopped or the vehicle is running, and the headlight is automatically turned on and off, and Although a control method that automatically turns on and off the headlight by detecting the degree of ambient light and darkness while driving is disclosed, the power consumption of the battery is reduced while driving with the headlight turned on. There remains a problem to save energy.

  In other words, in an electric vehicle that travels using the power stored in the battery, it is necessary to keep the power consumption of the battery as low as possible in order to extend the travel distance by a single charge, except for the motor for driving driving. One of the on-board devices that consumes a relatively large amount of battery power is a headlight.

  On the other hand, safety standards are set for the brightness (luminosity) of automobile headlights under the Road Transport Vehicle Law, and the minimum brightness under the Japanese law is 12,000 candela with a four-light high beam, and a maximum of 225,000 candela. It is stipulated that the vehicle must not be exceeded, and automakers ship the vehicle with the light intensity of the headlights initially set based on this safety standard. In addition, as for lamps applied to headlights, the use of LEDs with low power consumption and long life is being promoted.

  By the way, even when driving with the headlights turned on at night or in a tunnel, the brightness of the headlights may be slightly higher than the initial value on a highway or a highway tunnel that illuminates the road surface sufficiently brightly. Even if the light is dimmed, there is no risk of hindering normal driving, and experience shows that the road width is so wide that the driver is not dazzled when driving in a non-noro driving situation. In many cases, the headlight is temporarily turned off while the light is on.

  In view of this, the present invention automatically improves the brightness of the headlights according to the brightness of the road and the driving conditions of the vehicle, and improves the electric power consumption so that the power consumption of the battery can be kept low and energy saving driving can be achieved. An object of the present invention is to provide a headlight control device for an automobile.

In order to achieve the above object, according to the present invention, an electric vehicle headlight control device that travels with a battery as a power source is obtained with the optical sensor that detects the brightness of the road on which the vehicle is traveling and the optical sensor. A control unit that generates a brightness information signal based on the information; and a headlight control circuit that controls a light intensity of the headlight in response to the brightness information signal. The light control is performed in real time (Claim 1), and this control device can be configured in a specific manner as described below.
(1) An illuminance sensor or an in-vehicle camera mounted on the front of the vehicle toward the road ahead is used as the optical sensor means for detecting the brightness condition of the road.
(2) The headlight control circuit controls the output of the headlight by a pulse modulation method in response to the brightness information signal.
(3) Road traffic congestion information is given to the control unit that generates the brightness information signal, and the brightness of the headlight is controlled to be dimmed in real time.
(4) The headlight control device includes a mode changeover switch for switching the headlight between an automatic light control mode and a manual mode.

  According to the above headlight control device, the situation of the road on which the vehicle is traveling, for example, the presence or absence of a road illumination light, the brightness of the road illumination light, the traveling speed, etc., is detected, and the vehicle traveling environment changes from moment to moment. Correspondingly, it is possible to automatically control the brightness of the headlight in real time, thereby reducing the wasteful power consumption of the battery and realizing energy saving traveling.

  That is, the light intensity of the headlight is reduced from the initial value on a bright road, and the light intensity of the headlight is returned to the initial value on a dark road. In addition, when driving in heavy traffic due to traffic jams, the power consumption of the battery can be further reduced by automatically dimming the brightness of the headlight based on the VICS (registered trademark) information of the car navigation system or the vehicle speed information. It becomes possible.

1 is a basic block diagram of a headlight control device according to an embodiment of the present invention. FIG. 2 is a block diagram of a PWM signal generation circuit in the control unit of FIG. 1. 3 is a time chart showing a PWM control operation of a headlight by a control unit of FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on the examples shown in FIGS.
First, in FIG. 1, 1 is a headlight, 2 is a battery, 3 is a headlight control circuit (for example, a drive circuit of a PWM control system), 4 is a control unit in the previous stage, and the headlight 1 uses a battery 2 as a power source. Lighting and dimming control is performed as described later via the headlight control circuit 3.

  Further, the control unit 4 includes the brightness information of the traveling road acquired by optical sensors such as the optical sensor 5 and the camera 6, the traffic congestion information of the traveling road obtained by the navigation (car navigation system) 7, and the mode switching switch 8 The headlight automatic dimming mode and manual mode information is input, and the headlight control circuit generates a PWM signal based on these information and controls the dimming of the headlight 1 as described later.

  The light sensor (illuminance sensor) 5 and the in-vehicle camera 6 are mounted on the front of the vehicle to detect the road surface in front and the brightness of the surroundings. Further, the navigation 7 acquires traffic jam information (VICS (registered trademark) information) on the traveling road. A vehicle speed signal may be used instead of the navigation 7. The mode changeover switch 8 is a manually operated lever switch provided near the steering wheel of the vehicle.

Next, FIG. 2 and FIG. 3 show a circuit and operation for automatically dimming control of the brightness (luminosity) of the headlight 1 based on the brightness information of the traveling road acquired by the optical sensor 5 in FIG. explain.
That is, in the illustrated embodiment, the use efficiency of the electric power stored in the battery 2 is increased by adopting a pulse modulation method for the control of dimming the brightness of the headlight 1. The pulse modulation method includes a pulse width modulation method (Pulse Width Modulation) and a pulse frequency modulation method (Pulse Frequency Modulation). In the illustrated embodiment, the PWM method is adopted.

  In the control unit 4 shown in FIG. 2, the road brightness information acquired by the optical sensor 5 is converted into a voltage value corresponding to the road brightness by the optical sensor signal processing unit and input to the comparator of the PWM circuit. Here, the PWM signal is output by changing the duty ratio of the pulse width according to the carrier signal input from the carrier signal generator. FIG. 3 shows how a PWM signal is generated from road brightness information. That is, when the road is dark, the PWM signal is increased in duty ratio (long pulse width), and when the road is bright, the duty ratio is converted to be lower (short pulse width). Input to the write control circuit 3.

  Then, the headlight control circuit 3 performs switching control of the power supplied from the battery 2 by the input PWM signal, and automatically controls the dimming of the headlight 1 by supplying power according to the brightness of the road. . As a result, the power consumption of the battery can be reduced and the vehicle can save energy.

  Further, in the illustrated embodiment, road congestion information acquired by the navigation 7 of FIG. 1 is input to the control unit 4 so that the headlight 1 is dimmed. In other words, the environment in which the automobile travels includes a temporary stop of the vehicle due to traffic congestion on the road and a non-noro driving state. Under such an environment, even if the brightness of the headlight is reduced, the vehicle can travel without any problem.

  Therefore, in the present invention, as means for detecting traffic congestion on the road, VICS (registered trademark) information acquired by the navigation 7 or vehicle speed information obtained by the speed sensor is used, and the vehicle headlight 1 is detected in the same manner as described above. The power consumption of the battery can be reduced by automatically dimming the brightness.

  In addition, the headlight control device of the present invention includes a mode switch 8 (see FIG. 1) for switching between the automatic dimming mode and the manual mode, and manually adjusts the brightness of the headlight that is easy for the driver to drive as necessary. You can choose. In addition, this manual mode allows you to select the brightness of the headlight in several stages.For example, if the remaining battery capacity is low during driving, the headlight is forcibly dimmed to reduce battery power consumption. It is also possible to keep the value low.

DESCRIPTION OF SYMBOLS 1 Headlight 2 Battery 3 Headlight control circuit 4 Control part 5 Optical sensor 6 Camera 7 Navigation 8 Mode change switch

Claims (5)

  A headlight control device for an electric vehicle that runs using a battery as a power source, an optical sensor that detects the brightness condition of a running road, and a control that generates a brightness information signal based on information acquired by the optical sensor And a headlight control circuit that controls the light intensity of the headlight in response to the brightness information signal, and controls the brightness of the headlight in real time according to the brightness of the traveling road. Electric vehicle headlight control device.   2. An electric vehicle head according to claim 1, wherein the optical sensor for detecting the road brightness condition is an illuminance sensor or a camera mounted on the front of the vehicle facing forward. Light control device.   2. The headlight control device according to claim 1, wherein the headlight control circuit controls the output of the headlight by a pulse modulation method in response to the brightness information signal obtained by the control unit at the preceding stage. Automotive headlight control device.   2. The headlight control device according to claim 1, wherein the control unit that generates the brightness information signal is provided with road traffic jam information to control the headlight brightness in real time. .   5. The headlight control device according to claim 1, further comprising a manual switch for switching the headlight between an automatic dimming mode and a manual mode.