Lighting Service Lighting The main purpose of lights

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Lighting Service

Lighting Service

Lighting The main purpose of lights on a vehicle is to enable the driver

Lighting The main purpose of lights on a vehicle is to enable the driver to see and for other road users to be able to see the vehicle after dark and in other conditions of poor visibility. Requirements for the lights that must be fitted are: 1. Headlamps (minimum of two, one each side) 2. Side, rear, and number plate lamps 3. Direction indicator lamps (flashers) 4. Stop lamps (brake lights) 5. Rear fog lamp (at least one).

Bulbs Two commonly used types of bulb • Ordinary twin-filament headlamp bulb • Quartz

Bulbs Two commonly used types of bulb • Ordinary twin-filament headlamp bulb • Quartz halogen twin-filament headlamp bulb

Ordinary twin-filament headlamp bulb The filaments are made from tungsten wire and the glass

Ordinary twin-filament headlamp bulb The filaments are made from tungsten wire and the glass bulb is often filled with an inert gas such as argon. This permits the filament to operate at a higher temperature and increases the reliability. One of the filaments provides the main beam and the other filament, which is placed a little above centre, provides the dipped beam.

Quartz halogen twin-filament headlamp bulb Quartz halogen bulb is designed to give brighter light

Quartz halogen twin-filament headlamp bulb Quartz halogen bulb is designed to give brighter light and to prevent the evaporated tungsten from being deposited on the inside of the bulb.

some common bulbs Festoon has a tubular shape, used for number-plate and interior roof

some common bulbs Festoon has a tubular shape, used for number-plate and interior roof lighting. Miniature centre contact (MCC) 1 -5 watt has a bayonet cap consisting of two locating pins projecting from either side of the cylindrical cap. Cap 9 mm diam. It has a single central contact (SCC), with the metal cap body forming the second contacts Capless bulb have a semi-tubular glass envelope with a fl attened end, which provides the support for the terminal wires , used for panel lights, sidelights and parking - They are now very popular due to the low cost Single contact, small bayonet cap (SBC) Cap dia. 15 mm. The small 5 W bulb, is used for side or tail lights and the larger 21 W bulb is used for indicators, hazard, reversing and rear fog-lights. Double contact, small bayonet cap It has two fi laments, one end of each being connected to an end contact, and both of the other ends are joined to the cap body forming a third contact, which is usually the earth. used for the stop light and the other for the tail light. They are rated at 21 and 5 W (21/5 W) respectively.

Sidelights External Lights • A vehicle must have two sidelights each with wattage of

Sidelights External Lights • A vehicle must have two sidelights each with wattage of less than 7 W. • Most vehicles have the sidelights incorporated as part of the headlight assembly Rear lights • Not less than 5 W. Their position must be within 400 mm from the vehicle edge and over 500 mm apart, and between 350 and 1500 mm above the ground. Brake lights • There two lights are often combined with the rear lights. They must be between • 15 and 36 W each, with diffused light and must operate when any form of first line brake is applied. Reversing lights No more than two lights may be fitted with a maximum wattage each of 24 W. The light must not dazzle and either be switched automatically from the gearbox or with a switch incorporating a warning light. Safety reversing ‘beepers’ are now often fitted in conjunction with this circuit, particularly on larger vehicles.

External Lights Day running lights • These lights come on with the ignition and

External Lights Day running lights • These lights come on with the ignition and must only work in conjunction with the rear lights. Their function is to indicate that the vehicle is moving or about to move. They switch off when parking or headlights are selected. Rear fog lights • One or two may be fitted but, if only one, then it must be on the offside or centre line of the vehicle. Front spot • If front spot lights are fitted (auxiliary driving lights). If the lights are non-dipping then they must only operate when the headlights are on main beam. • Spot lamps are designed to produce a long beam of light to illuminate the road in the distance. • Front fog lamps may only be used in fog or falling snow. • They are designed to produce a sharp cut off line such as to illuminate the road just in front of the vehicle but without reflecting back or causing glare.

Headlight Reflector The object of the headlight reflector is to direct the random light

Headlight Reflector The object of the headlight reflector is to direct the random light rays produced by the bulb into a beam of concentrated light by applying the laws of reflection

Headlight Levelling The principle of headlight levelling is very simple, in that the position

Headlight Levelling The principle of headlight levelling is very simple, in that the position of the lights must change depending on the load in the vehicle. Manual headlight levelling Automatic headlight levelling

Repair and maintenance Some service and repair operations may require components and cables to

Repair and maintenance Some service and repair operations may require components and cables to be disconnected. In such cases, the procedures for taking connectors apart should be observed and care taken to avoid damage to the pins. Damage to pins may cause the connection to develop a high resistance or to fail completely. Should it be necessary to probe connections, in an endeavour to trace a fault, every effort should be made to prevent damage to waterproofing and electrical insulation.

Circuit protection - fuses The purpose of the fuse is to provide a ‘weak’

Circuit protection - fuses The purpose of the fuse is to provide a ‘weak’ link in the circuit that will fail (blow) if the current exceeds a certain value and, in so doing, protect the circuit elements and the vehicle from the damage that could result from excess current. The fuse is probably the best known circuit protection device. Fuses have different current ratings and this accounts for the range of types available. Care must be taken to select a correct replacement and larger rated fuses must never be used in an attempt to ‘get round’ a problem. Many modern vehicles are equipped with a ‘fusible link’ that is fitted in the main battery lead as an added safety precaution. It is common practice to place fuses together in accessible place on the vehicle. Another feature of the increased use of electrical/electronic circuits on vehicles is an increase in the number of fuses to be found on a vehicle Types of fuses

Headlight Beam Setting To set the headlights of a car using an aiming board

Headlight Beam Setting To set the headlights of a car using an aiming board the following procedure should be adopted. 1. Park the car on level ground square on to a vertical aiming board at a distance of 10 m if possible. The car should be unladen except for the driver. 2. Mark out the aiming board as shown below. 3. Bounce the suspension to ensure it is level. 4. With the lights set on dip beam, adjust the cut-off line to the horizontal mark, which will in most cases be 1 cm below the height of the headlight centre for every 1 m the car is away from the board. * The break-off point should be adjusted to the centre line of each light in turn.

Gas discharge headlamps (GDL) GDL are now being fitted to vehicles. They have the

Gas discharge headlamps (GDL) GDL are now being fitted to vehicles. They have the potential to provide more effective illumination and new design possibilities for the front of a vehicle. The new headlamps make a significant contribution towards improving aerodynamic styling and suitable lighting positions because they can be relatively small. The GDL system (also known as high intensity discharge or HID) consists of three main components. the operating principle of a GD bulb Lamp This operates in a very different way from conventional incandescent bulbs. A much higher voltage is needed. Ballast system This contains an ignition and control unit and converts the electrical system voltage into the operating voltage required by the lamp. It controls the ignition stage and run up as well as regulating during continuous use and finally monitors operation as a safety aspect. Ballast system to control a GDL

Headlamp The design of the headlamp is broadly similar to conventional units. To meet

Headlamp The design of the headlamp is broadly similar to conventional units. To meet the limits set for dazzle, a more accurate finish is needed, hence more production costs are involved. The source of light in the gas discharge lamp is an electric arc, and the actual discharge bulb is only about 10 mm across. Two electrodes extend into the bulb, which is made from quartz glass. The gap between these electrodes is 4 mm. The distance between the end of the electrode and the bulb The spectrum of light produced by the GDL compared with that contact surface is 25 mm - this corresponds to the dimensions from a halogen H 1 bulb. of the standardized H 1 bulb. At room temperature, the bulb contains a mixture of mercury, various metal salts and xenon under pressure. When the light is switched on, the xenon illuminates at once and evaporates the mercury and metal salts. The high luminous efficiency is due to the metal vapour mixture. The mercury generates most of the light and the metal salts affect the colour spectrum. The difference in output between the D 1 and H 1 bulbs

The following four stages are run through in sequence to start the D 1

The following four stages are run through in sequence to start the D 1 (GDL) lamp, . • Ignition - a high voltage pulse causes a spark to jump between the electrodes, which ionizes the gap. This creates a tubular discharge path. • Immediate light - the current flowing along the discharge path excites the xenon, which then emits light at about 20% of its continuous value. • Run-up - the lamp is now operated at increased wattage, the temperature rises rapidly and the mercury and metal salts evaporate. The pressure in the lamp increases as the luminous flux increases and the light shifts from the blue to the white range. • Continuous - the lamp is now operated at a stabilized power rating of 35 W. If the GDL system is used as a dip beam, the self-levelling lights are required because of the high luminous intensities.

The xenon bulb is a micro-discharge bulb filled with a mixture of noble gases

The xenon bulb is a micro-discharge bulb filled with a mixture of noble gases including xenon. • The bulb has no filament, as is the case with a halogen bulb, but the light arc is created between two electrodes. • As is the case with other gas discharge bulbs, the xenon bulb has an electronic starter for quick ignition, and requires an electronic ballast to function properly. • The xenon bulb provides more than twice the amount of light of a halogen bulb, while only consuming half the power, So the driver can see more clearly, and the car has more power for other functions. • it is environmentally friendly. • The clear white light produced by the xenon bulb is similar to daylight. • The bulb need only be replaced in exceptional cases. The xenon bulb

The xenon bulb The light produced by a xenon bulb is, in fact, not

The xenon bulb The light produced by a xenon bulb is, in fact, not blue but white, falling well within the international specifications for white light – the light only appears blue in comparison to the warmer ‘yellow’ light produced by halogen. However, it clearly appears white in comparison to daylight. Technically speaking, it is possible to adapt the light colour produced, but this would lead to a substantial loss of intensity, thereby cancelling out the particular advantages. The xenon lighting

Ultraviolet (UV) headlights The GDL can be used to produce ultraviolet (UV) lights. Since

Ultraviolet (UV) headlights The GDL can be used to produce ultraviolet (UV) lights. Since UV radiation is virtually invisible it will not dazzle oncoming traffic but will illuminate fluorescent objects such as specially treated road markings and clothing. . The UV light will also penetrate fog and mist, as the light reflected by water droplets is invisible. It will even pass through a few centimeters of snow. Cars with UV lights use a four-headlamp system. This consists of two conventional halogen main/dip lights and two UV lights. The UV lights come on at the same time as the dipped beams, effectively doubling their range but without dazzling. Two-stage blue filters are used to eliminate visible light. Precise control of the filter colour is needed to ensure UVB and UVC are filtered out, as these can cause eye damage and skin cancer. This leaves UVA, which is just beyond the visible spectrum and is used, for example, in suntan lamps. However, some danger still exists; for example, if a child were to look directly and at close range into the faint blue glow of the lights. To prevent this, the lights will only operate when the vehicle is moving.

Light emitting diode (LED) Most of the major manufacturers now use of LEDs for

Light emitting diode (LED) Most of the major manufacturers now use of LEDs for some lighting applications. LEDs quickly found applications in the interior of the vehicle, particularly in dashboard displays. However, until recently, legislation has prevented the use of LEDs for exterior lighting. The advantages of LED lighting are 1. clear, 2. the greatest being reliability, 3. they turn on quicker than ordinary bulbs, 4. LED have a typical rated life of over 50 000 hours, compared with just a few thousand for incandescent lamps. 5. ‘turn-on’ time is important; the times are about 130 ms for the LEDs, and 200 ms for bulbs 6. Heavy vehicle side marker lights are an area of use where LEDs have proved popular Disadvantages LEDs are more expensive than bulbs

Infrared Lights Infrared thermal-imaging systems are going to be fitted to cars. The Cadillac

Infrared Lights Infrared thermal-imaging systems are going to be fitted to cars. The Cadillac division of General Motors has a system called ‘Night Vision’ as an option. After ‘Night Vision’ is switched on, ‘hot’ objects, including animals and people show up as white in thermal image, Every object at a temperature above absolute zero (– 273. 15 °C) emits some kind of infrared radiation. On the vehicle system a camera unit sits on headlamptype mountings in the centre of the car, behind the front grille. Its aim is adjusted just like that of headlamps. The mid-grille position was chosen because most front collisions involve offset rather than full head-on impacts. However, the sensor is claimed to be tough enough to withstand 9 mph (14. 5 kph) bumper impacts anyway. The sensor is focused 125 m ahead of the car. The outer lens of the sensor is coated with silicon to protect it against scratching. Behind this two lenses are made of black glass called tecalgenite. This is a composite material that transmits infrared easily but visible light will not pass through it. Night vision system in use

Other lighting technology mono-colour technology With this technology, in addition to the traditional red

Other lighting technology mono-colour technology With this technology, in addition to the traditional red functions (stop, tail lamp and fog), the reverse and turn signal functions appear red when not in use, but emit white and yellow light respectively when functioning. Several technologies make this possible. Bending Light This system consists of a bi-xenon projector, or reflector headlamp, that can rotate up from its normal position. An additional projector, reflector, or a combination of the two can be used to deliver more light into a road bend. The actuation of the motorized lighting unit, within each headlamp assembly, is controlled by an electronic control unit, which employs signals from the steering wheel and wheel-speed sensors. A link to a satellite navigation system (GPS) can also be used if required. Dynamic bending light and normal lighting

Bending Light includes three distinct lighting types: • Motorway Lighting – typically above 80

Bending Light includes three distinct lighting types: • Motorway Lighting – typically above 80 km/h (50 mph), the low-beam function of the head-lamp is raised using a signal received from the wheel-speed sensor to actuate a self-levelling system, which increases driver visibility at high speeds. • Adverse Weather Lighting – provides, under reduced-visibility conditions in fog, rain and snow, additional illumination to help keep track of road edges, while light is removed from the foreground to reduce reflection from the wet road. • Town Lighting – in well-illuminated urban areas the light beam is lowered and lateral light is increased, improving pedestrian and cyclist identif cation at crossings as well as reducing dazzle. Bending Light is an intelligent headlamp system that optimizes the night-time illumination of road curves by directional control of vehicle headlamps. To turn an increased quantity of light into road bends automatically, Bending Light systems adopt several flexible design approaches. Dynamic Bending Light (DBL) uses a Bi. Xenon lamp (projector or reflector type) housed in each headlamp unit, together with an electronic actuator and an electronic control unit. This design facilitates the horizontal rotation of the Bi-Xenon lamp by up to 15° from the normal ‘straight-ahead’ position). This function is controlled by a microcontroller linked to the vehicle’s data network with real time inputs from both the steering angle and speed sensors. Fixed Bending Light (FBL) employs an additional projector or reflector type lamp integrated into theheadlamp unit at a 45° angle.

Intelligent lighting

Intelligent lighting

Single light source lighting It is possible to use a gas discharge lamp (GDL)

Single light source lighting It is possible to use a gas discharge lamp (GDL) as a central source for vehicle lighting. Development of this new headlamp system allows a reduction in headlamp dimensions for the same output or improved lighting with the same dimensions. The principle is that light from the ‘super light source’, is distributed to the headlamps and other lamps by a light-guide or fibre-optic link. The light from the GDL enters the fibre-optics via special lenses and leaves the light-guide in a similar manner. A patterned covered lens provides the required light distribution. Shields can provide functions such as indicators, or electro-chromatic switches may even become available. GDL as central light source for all the vehicle lights

Circuits symbols

Circuits symbols