02-10-2012, 03:55 PM
Automatic upper dipper system
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ABSTRACT
The number of vehicles on our roads is burgeoning day by day. This is turn forced almost all this vehicle manufactures to think about the extra safety instruments and electronic controls to attach with these products for giving the users a safety derived in all road conditions through a mass flow traffic. If asked, one should always mention that the right driving is very cumbersome due to the dazzling light problems and the frequent dipping of headlights by manual means that often causes fatigue to the driver particularly at the time of peak traffic. So naturally to get rid of this perennial problem, an automatic mechanism has to come up to dip the headlamp automatically whenever required. For keeping a motor vehicle under perfect control and reins of the driver, different types of controls and accessories are provided in an automobile around the driverâ„¢s seat, on the dashboard and at the footboard. Simply, 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.
INTRODUCTION
The number of vehicles on our roads is burgeoning day by day. This is turn forced almost all this vehicle manufactures to think about the extra safety instruments and electronic controls to attach with these products for giving the users a safety derived in all road conditions through a mass flow traffic. If asked, one should always mention that the right driving is very cumbersome due to the dazzling light problems and the frequent dipping of headlights by manual means that often causes fatigue to the driver particularly at the time of peak traffic. So naturally to get rid of this perennial problem, an automatic mechanism has to come up to dip the headlamp automatically whenever required.
For keeping a motor vehicle under perfect control and reins of the driver, different types of controls and accessories are provided in an automobile around the driverâ„¢s seat, on the dashboard and at the footboard. There are controls like clutch, brake pedal, accelerator pedal, and sharing the same importance, the dimmer switch is changed with time, and its pace in the filed of automobile safety is one of the uppermost.
Simply, 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.
Construction
The present day headlights are the outcome of a lot of research and development. Earlier a single electric bulb of the carbon filament type was employed. 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. It may be mentioned that the bulb itself and the intensity of light fall off towards the outer portion of the beam block a small amount of light.
From figure it may be seen that if the bulb filament is moved from position Ëœdâ„¢, the focus of reflector, to a position Ëœaâ„¢, the light beam Ëœabcâ„¢ will no longer be a parallel one but will become divergent. On the contrary, if the filament is moved to position Ëœfâ„¢ the beam will take the course a shown by Ëœfbgâ„¢ and will meet at a point on the axis of the bulb. It may be mentioned that by a single adjustment of the bulb, the beam cane be concentrated at a ore-determined distance ahead of the vehicle in order to give a spot light effect.
Control of Headlight Beam
The circular beam can be spread horizontally to any desired extent with the help of prisms, molded in the inside of the headlight cover glass, as shown in the figure. The horizontal light intensity can be controlled in any desired way by a suitable design of the headlight. The circular beam can also be controlled in the vertical direction with the help of prisms molded in front of the glass, thus redirecting the light rays in the downward direction. This way the downward reflected beam does not obstruct the vision of the other road users coming from the opposite side. With these two combinations, any required main beam illumination, combined with side illumination nearer to the vehicle can be produced.
RECENT DEVELOPMENTS
Technology improves day and day in the field of automobile headlamp construction and it left out the earlier single electric bulb of the carbon filament type and in place modern sealed beam headlights are using nowadays. The light circuits of todayâ„¢s vehicles can consist of more that 50 light bulbs and hundreds of feet of wiring. Incorporated within these circuits are circuitsâ„¢ protector, relays, switches lamps, and connectors. In addition more sophisticated lighting systems use computers and sensors. The lighting circuit consists of an array of interior and exterior lights, courtesy lights and so on. Federal laws largely regulate the lighting circuits, so the systems are similar between the various manufactures.
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. HID lamps produce light in tooth ultraviolet and visible wavelengths. This advantage allows highway signs and other reflective materials to glow. This type lamp first appeared on select models from BMW in 1993, Ford in 1995, and Porche in 1996.
These lamps do not relay on growing filament for light. Rather light is provided as a high voltage bridges an air gap between two electrodes. The presence of inert gas amplifies the light given off by the arching. More than 15,000 volts are used to jump the gap between the electrodes. To provide this voltage, only about 80 volts is required to keep current flow across the gap. The great light output of these lamps allows the headlamp assembly to be smaller and lighter. These advantages allow designers more flexibility in body designs as they attempt to make their vehicles more aerodynamic and efficient.
HEADLIGHT DAZZLE
The dazzle effect is one of the major problems faced by a driver in night driving. So one has to stop the high intensity light from the eyes of the incoming driver or road users to prevent the dazzle effect. Automatic Dipper is one such mechanism, which is employed for safety night driving without the intense dazzling effects. Without much efforts from the driver which otherwise has to dim the lights every seconds by manual means may lead to fatigue to the driver especially during peak traffics. So it will be better to know Ëœwhat is meant by dazzleâ„¢ and Ëœwhat all devices are often used in preventing dazzle effectâ„¢ before mentioning the advantages and uses of an auto dipper.
DIPPING OF HEADLIGHTS
When the vehicle is driven on the highways, it is required that light beam should be of high density and should illuminate the road at a distance sufficiently ahead. However when a vehicle coming in the opposite direction approaches a vehicle fitted with such headlights, driver of that vehicle will experience a glare, which will blind him. To avoid this, a separate filament is fitted at such a position that that light beam from this filament is deflected both down and sideways so that the driver of the oncoming car is not blinded. Some of the ways in which this can be achieved are shown in the following figure.
The main filament may be placed at the focus with the dipper filament slightly above it or the main filament and the dipper filament may be placed slightly below and above the focus respectively, with the reflector tilted. Another popular method is to place the main filament at the focus and the dipper filament slightly in front of the same with a mental shield placed below the dipper filament. In this only this upper half of converging beam comes out of the reflector. Thus it prevents the other rays from setting reflected from the lower half of the reflector and emerging in the upward direction to cause glare.