Follow the light

Car headlamps that swivel to light the way round corners will be available next year using sophisticated electronic control.

Within the next three years the industry expects lights that automatically change their beam pattern to suit town or motorway driving or bad weather conditions. The technology will also allow for changes from driving on the left to right when travelling between the UK and continental Europe.

Mercedes-Benz and Vauxhall are the first car makers to announce they will adopt the system when European regulations change in March. Both worked with automotive lighting specialist Hella to develop their system. Visteon’s similar Advanced Front Lighting System (AFS) will be available at the same time, but the first customer has yet to be announced.

The idea of lights that shine in the direction the car is turning has been around almost as long as cars have had lights. But early attempts created problems, and regulations specifying a standard pattern were introduced. The idea was last tried by Citroen, which fitted swivelling auxiliary lights to the DS model in the mid-1960s.

The problem in the past was that controlling the swivelling of the lights by a mechanical link to the steering alone does not give the optimum result under a range of speeds and severity of corner. Now, with the advent of more sophisticated electronic control, car makers have successfully argued for a change in the regulations covering beam patterns for European cars.

Both the Visteon and Mercedes systems will use sensors measuring steering inputs and vehicle speed to control an electric motor on each lighting unit.

Visteon’s system allows the beam to rotate horizontally by up to 4 degrees inward and 13 degrees outward, as well as by 6 degrees vertically. The lights are capable of turning asymmetrically, so that on a right-hand corner the right-hand light begins to swivel before the left one, said Visteon head of lighting development for Europe Dr. Rainer Neumann.

The Mercedes system is specifically designed for the E-class’s high-intensity xenon discharge headlamps. It swivels on both low and high beam.

Mercedes claims that the illuminated distance on entering a 190m radius curve is improved from 30m to 55m. Both systems can dynamically compensate for vertical pitching motions, but Vitreon will not offer this on the base version of its system for the mainstream market.

Independent tests of the Visteon system by TUV Rheinland Berlin Brandenburg found that on average 20 per cent more unlit obstacles were recognised with AFS lamps and that the speed of drivers’ reactions in an emergency braking test improved by 14 per cent.

A further change to the regulations, expected around 2005, will allow a second generation of adaptive lights that automatically provide a long, slim beam for high-speed motorway driving and a broader, shorter beam when driving slowly in towns and cities. In bad weather the beam would be modified to reduce the amount of light reflecting off a wet road surface and dazzling oncoming drivers.

Future systems will also be able to respond to information from satellite navigation systems, say both Mercedes and Visteon.

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