Lighting Control System to Control Light Beam of Vehicle During Failure
Asst.Prof. Jyotirmayi Purohit
Chapter 1: Introduction
1.1 Introduction
Modern automotive vehicles variety of headlamps that are typically controlled to alternately generate a low light beam for short distance and a high light beam for long distance. The low light beam is provided in the areas where street light or likewise illuminated place already exists, whereas the high light beam is provided in highways or such roads where provision of street lights does not exists. Failure of these headlamps even for a small duration of time may critically effect the driving experience. Specifically, when the vehicle is at a high speed, failure of the low light beam or the high light beam even for few seconds may lead to situations prone to accidents.
Conventional modern vehicles comes with an Automatic High Beam (AHB) control system to maximize the use of high beam road illumination and control exterior lighting functions when appropriate. FIG. 1.1 illustrates mode of operation of head light control system during normal condition. The control system includes a light source i.e. Head light filaments connected to an electronic control unit. The light source includes a high beam head lamp and a low beam head lamp. The electronic control unit is connected to an input terminal i.e. Head light switch to receive input associated with the light source. During the normal condition, when the input terminal indicates that the high beam is switched ON, the Electronic control unit activates both the high beam head lamp and the low beam head lamp simultaneously. However, when the input terminal indicates that the low beam is switched ON, only the low beam head lamp remains activated as shown in the FIG. 1.2
FIG. 1.3 illustrates mode of operation of control system during failure condition. When the input terminal indicates that only the low beam is switched ON, if the low beam filament burns out, fuse blown, wire cut or the low beam relay fails then the high beam lamp cannot be activated automatically as there is no failure feedback to the control system as shown in the FIG. 1.4. During such failure condition, the driver has to manually switch ON the high beam lamp as soon as possible. This results in accidents on road due to lack of visibility on the road.
Accordingly, there is a need of system that overcomes the above mentioned problem
