Adaptive Headlights in Cars
Back in the day when automotive headlights were invented in 1879, they were kerosene oil-burning lanterns. Over the years as technology progressed we saw electric, halogen and xenon lights get attached to our cars. In 2008 Audi, used LED lights and in 2014 BMW came up with laser lights.
Automotive headlights have been on road for nearly 135 years but driving at night is still considered to be dangerous. 51% of fatalities in road accidents occur at night. There are about 445000 accidents every year in weather-related calamities. 30% of people are distracted by glare in the night. Overall about 300 billion dollars are lost per annum in social and economic damages from road accidents.
With technological advancements in headlights, nowadays many companies are focusing on adding adaptive headlights. They help the drivers see better on dark curved roads. The active lights pivot in the direction of traffic when a driver steers around curves or corners. The headlights adjust on steering wheel movement and vehicles speed to illuminate the road ahead.
Introduction Adaptive Front Lighting System:
An adaptive front lighting system is not just a uni-direction lighting, the illumination of the road ahead not only covers the road ahead but also provides extra illumination of the road during cornering and reduces glare to the oncoming vehicle by not beaming the light in its direction. This not only improves the safety due to incoming traffic but also increases the illumination of the road. These features enable the driver to have extra visibility and reduced fatigue due to incoming lights by concentrating lights in the region of interest. This system takes into account the weight into the car by auto-levelling the lights.
This system communicates with the vehicle by CAN network and reads parameters like Steering Angle, Speed, Yaw, rain sensor and a Camera Unit.
The difference in the illumination in the lights can be checked in the below video.
Types of Beams in an AFS(Adaptive Front Lighting System)
Adaptive Front-lighting system provides the following categories of beams:
Adaptive headlight systems are made up of several sub-components that are monitored and controlled by an Electronic Control Unit (ECU). The sub-components include
- Wheel Speed Sensor– Monitors the speed of rotation of each wheel
- Yaw Sensor– It tracks vehicle’s side to side movement. For example; when turning around the corner.
- Steering Input Sensor– It monitors the angle of the steering wheel and small motors attached to each headlight.
- Motors– They are attached to each headlight. (An Alternative to this is focussed LED Unit, that enables and disables selective lighting components to achieve different illumination)
- Level Sensor– Sends the information about the vehicle’s position to the ECU
- Rain Sensor System- This sensor is fitted to the vehicle and the data is fetched via CAN network.
- ECU– This is the brain and considers all sensors information for generating the required illumination of lights.
Working of Adaptive Headlights
Headlights used most widely nowadays are made up of Light Emitting Diodes (LEDs) which are brighter and use less energy. At night, the glare-free connected drive high beam improves visibility. A camera detects the traffic situation at night and passes information on to the headlights. It calculates the optimal beam pattern up to 100 times per second.
The headlights adapt the light distribution according to the traffic situation. High beam remains active without glaring any road traffic participants. Oncoming traffic is already detected in the great distance and the high beam light is distributed accordingly.
When an oncoming car passes, the headlight automatically switches to low beam. When a preceding car is detected by the camera the headlights open up to a tunnel. High beam stays active on both sides of the preceding car without glaring at the driver.
The headlights are optimally illuminated without the other drivers being bothered. With this intelligent light control, dangerous situations can be detected sooner where they can be prevented.
Types of Headlights
- Halogen Headlights– The halogen lamp uses halogen gas to increase its brightness. They emit a yellowish light at a range of about 100 meters. They are not very efficient as a lot of energy is wasted as heat rather than utilised as light.
- Xenon Headlights– They are also known as High-Intensity Discharge (HID). Xenon gas is used that is electrically charged. It produces a bluish-white light, close in colour to natural light. They are expensive but long lasting and efficient. They have a high time lag to start and reach to their complete brightness thereby having an extra halogen bulb for the high and passing beams. Thus a car has four bulbs in two units.
- Bi-Xenon Headlights– Contrary to the name, it uses one xenon lamp for its high beam which is moved or shaded each time low beam is to be provided. This is cheaper and occupies less space.
- LED Headlights– They produce light from the movement of electrons. It is simple and highly efficient. They have no time lag and have a high range to emit light. They emit light closer in colour to daylight. They can be used both as high beam and low beam of light.
- Laser Headlights– They simulate a gas between the laser beam which glows exceptionally bright and powerful light. They have a very high range of emitting light but it is expensive and therefore used only in luxury cars.
Companies using Adaptive Lighting System
- Audi- The adaptive lighting system is available for the xenon plus headlights that further strengthens to the security of night time driving
- BMW- It is a standard feature present in most models
- Buick- Buicks adaptive articulating headlights available on Regal and LaCrosse
- Cadillac- Adaptive forward lighting is available on CT6, ATS, CTS, ELR, XTS, CTS-V, XT5, Cadillac escalade
- Ford– Ford S-Max, Ford Galaxy, Edge SUV
- Hyundai- Adaptive front lighting in Equus 2016, Hyundai Genesis, 2017 Elantra
- Inifinity- 2016 Q60 model, QX 50, Q50
- Jeep- Selected Grand Cherokee models
- Kia- Kia Sportage, Kia K7, Kia K900
- Land Rovers- Range Rover, Range Rover Sport, Range Rover Evoque
- Mazda- Mazda 3, Mazda CX-5, 2016 Mazda MX-5 Miata, Mazda 6
- Mercedes Benz- B-Class, C-Class, CLA-Class, E-Class, GL-Class, GLA-Class, GLC-Class, GLE-Class, GLK-Class, M-Class, ML-Class, SL-Class, and SLK-Class
- Mini- Mini Hardtop 2 Door
- Nissan- Qashqai, 2016 GT-R, X-Trail
- Porche- Most models have adaptive lighting system
- Subaru- Subaru Outback
- Tesla- Model S, Model X
- Toyota- Toyota Prius
- Volkswagen- Golf, Golf Sportwagen, GTI, Jetta, Touareg, Tiguan, Eos and CC
- Volvo- XC60 and S60
Headlights in Harsh Weather Conditions
During a rainstorm, the lights will get reflected off a nearby raindrop. The headlights of a car driving at night will not only brighten the road but also brighten the drop causing distracting flashes. This technology uses a high-speed adaptive projection to illuminate the roads but not the drops.
When a beam of light is emitted from a car, there are a few rays that are reflected off the raindrops that cause the disturbance. If we momentarily switch just those rays of light off for an imperceptible fraction of a second, then that will give the driver the impression, these lights can see through rains causing no hindrance to the driver while driving. Using a digital camera the reactive illumination system tracks the movement of each raindrop, as the computer predicts what each will be a few seconds later.
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