AUTOMATIC HEAD LIGHT PRESENTED BY JAGADEESH CHANDRA BABU K.P

OVERVIEW  INTRODUCTION  HEAD LAMPS  LIGHT SOURCE  CONSTRUCTION  TWO FILAMENT BULBS  HEAD LIGHT DAZZLES  AUTOMATIC DIPPER  APPLICATION OF AUTOMATIC DIPPER  WORKING OF AUTOMATIC DIPPER  RECENT DEVELOPMENT  CONCLUSION

INTRODUCTION The number of vehicles on our roads is burgeoning day by day. An automatic dipper is a unit, which can automatically judge when the headlight beam needs to be lowered, and which dip the headlamp from which beam to a dipped beam. As the dipper unit is well connected to the lighting system of the vehicle, we have to look short into the type and construction of a head light before discussing the wiring diagram or the construction of Automatic dippers.

HEAD LAMPS  The modern lighting system consists of switches, lamps, wiring harness, and fuses or circuit breakers.  It may be mentioned that the primary purpose of the headlight design is to produce illumination over considerable distance ahead of the vehicle and enable the driver to drive at reasonable speeds at night with safety.  But the provision should also be made that the drivers of other vehicles coming from the opposite direction to not experience a glare.  For this purpose a dipped or meeting beam is also provided for maintaining the reasonable speed with safety without dazzling the coming driver.

LIGHT SOURCE There are two kinds of light sources  One that emits light.  Other that reflects lights. The headlight is composed of three elements:  The light filament that gives off light when a current flows through it.  The parabolic reflector that reflect the light in front.  The lens that refracts of distorts the light beam into an illuminating pattern.

CONSTRUCTION  Earlier the bulb was placed at the focus of a parabolic silvered reflector in order to give a parallel beam of light.  The following figure shows a parabolic reflector with bulb, the lines showing light rays emitted from the filament of the bulb in all directions.  This type of headlight given a parallel light beam, that saves greater illumination nearer the axis.

The parabolic reflector showing light rays emitted from the filament of the bulb

The effect of changing the position of filament on the nature of the light beam

TWO FILAMENT BULBS  The first major advancement in headlight design took place with the introduction of pre-focused bulbs.  In two filaments modern headlights there uses a two-filament bulb with a fixed reflector.  It has two filaments, one for normal driving and the other for city driving or for overtaking.

A double – filament lamp

HEADLIGHT DAZZLES  The dazzle effect is one of the major problems faced by a driver in night driving  Automatic Dipper is one such mechanism, which is employed for safety night driving without the intense dazzling effects

The dazzling effect can be prevented by,  Reducing the brightness of the headlights of the vehicles.  Stopping high intensity light from entering the yes of on-coming drivers or road users.  Reducing the contrast between the surrounding area and the headlight of the vehicle.

AUTOMATIC DIPPER An autronic dipper is a unit which can automatically judge when the head light beam needs to be lowered. The auto dippers are basically switches, which dip the headlamp from high beam to a dipped beam if a certain amount of light falls on its photo sensor. It holds the lights on upper, or high, beam until a car trigger the system so that it shifts the headlamps to the lower beam.

APPLICATION OF AUTOMATIC DIPPER  In the ‘Autronic Eye’, the photoelectric cell senses the intensity of light from the oncoming vehicles and dips the heedful.  The driver does not have to control the headlights.

WORKING OF AUTO DIPPER

RECENT DEVEOPMENT Halogen lamps  The halogen lamps are mostly introduced and consist of tungsten filaments in the atmosphere of some halogen element such as chlorine, bromine, or iodine. The tungsten evaporated from the filaments reacts with halogen gas to form tungsten halide, which is decomposed back into halogen and tungsten due to high temperature at the filaments, thus causing the tungsten to get redeposit on the filaments.

Composite headlights  Many of today’s vehicles have a halogen head light system using a replaceable bulb. This system is called composite headlights. By using the composite headlight system, vehicle manufacturers are able to produce any style of headlight lens by desire.

HID Headlamps  High Intensity Discharge (HID) headlamps are the latest headlight development. These headlamps put out three times more light and twice spread on the road then conventional halogen headlamps. They also use about two-thirds less power to operate will last two to three times larger

CONCLUSION  Auto dippers are devices, which will attain more and more importance in the forthcoming years.  It is a device with a very bright future.  The number of vehicles and the condition of the roads are improving very fast and the day is near, when the driving regulation, nature of traffic etc

THANK YOU