Audi A8

Emotional interior lighting in the Audi A8
Major changes have taken place in vehicle interior lighting in recent years. The simple light fitted to the roof liner has been replaced by integral concepts that provide ambient mood lighting. This change in direction has been accompanied by new developments in the field of light sources. Until just a few years ago, only conventional bulbs were used for interior lighting, with a very few exceptions. Nowadays, light-emitting diodes (LEDs) are becoming more common. Their small size, long service life and low power consumption open up completely new opportunities for lighting design. This potential has been fully exploited in the Audi A8. Bertrandt Ingolstadt partnered Audi in the technical implementation of the newly designed lighting components.

Project requirements
Interior lighting is playing an increasingly important role particular in luxury class cars. Alongside traditional applications, such as reading lights and interior lights, new functions are being added. Interior lighting now enables storage compartments and buttons to be easily identified, influences the mood inside the car and creates a pleasant ambience. Another essential task for interior lighting is to attract attention to safety features. In addition, efficiency is becoming a more significant factor, as lighting uses energy and contributes to the vehicle’s fuel consumption.

In a premium car such as the Audi A8, additional requirements are placed on the interior lighting, including:

 

  • high levels of functionality
  • individual adjustment options
  • creating an emotional experience

 

New lighting concepts were developed to meet these demands. In the course of its project coordination and design support activities, the “Lighting and Vision Systems” team from Bertrandt Ingolstadt also contributed to the technical implementation. As well as providing project management services, including development for volume production, Bertrandt created the concept designs and developed the new lights in close collaboration with the systems suppliers. The combined lighting expertise of Audi and Bertrandt enabled the new lighting functions to be produced and integrated into the Audi A8. The new interior and ambient lighting of the Audi A8 sets the standard for future generations of cars.

Light sources improve safety and create a special atmosphere

Interior and ambient lighting
The interior lighting of the Audi A8 consists of a variety of different light sources. Three light strips run along the sides of the roof liner on the right and left between the grab handles and around the lighting module to provide the interior and ambient lighting. In interior lighting mode, the reading lights are also switched on. These are located in the lighting module and at the sides next to the light strips. This provides bright lighting for the entire interior of the car, in particular at night. In contrast, in ambient lighting mode the light strips shimmer to create a pleasant atmosphere when the car is on the move. In this mode, larger areas such as the upholstery, door pockets and footwells are also illuminated discreetly using fibre optic cables and small lights to make the interior seem larger. Another striking feature is the centre console, which has a top panel that appears to float freely above it and in the dark is highlighted by the fibre optic lights that surround it.

Coming home/leaving home lights and door warning lights

The external door handles have been integrated into the coming home/leaving home lighting system which illuminates the handle recesses and the ground in front of the closed door. When the door is opened, the illuminated sill trim made of aluminium is the first feature to meet the eye. An elongated trapezoid shape in the trim, with or without model name, is lit by a fibre optic cable and LEDs fitted underneath. When the driver or passengers enter or leave the car, the entry light built into the door trim illuminates the ground to allow any obstacles to be easily identified. At the same time, the red door warning light is switched on to make passing vehicles aware that the door is open, which offers additional safety benefits.

Supplier management

As part of the development process, Bertrandt managed the interface between the OEM and the systems suppliers. This included DMU (digital mock-up) data management, producing technical documentation, positioning the lights in the virtual vehicle and coordinating with the different departments at Audi, such as design and surfacing. The requirement for an even distribution of light presented a special challenge, which Audi and Bertrandt met by providing support to Audi’s standard suppliers. New ideas were put into effect in concept designs and validated by Audi using simulation processes.

Bertrandt Ingolstadt created the reading light concept. The housing, lens, push button and accompanying retainers were designed and engineered by Bertrandt.

Creating lighting scenarios
The latest trend in vehicle interior lighting is to move away from individually controlled light sources and to create integral lighting scenarios. This concept has been applied consistently in the case of the Audi A8. The individual light sources are grouped together to form lighting scenarios, so that the lighting experience begins as soon as the car is remotely unlocked. The light spreads evenly across the driver’s seat, the passenger’s seat and the rear seats. In addition, the leaving home function is activated and the relevant lights are switched on. Another scenario comes into play when one door is opened. The light focuses on the seat inside the door and invites the driver or passenger to climb aboard. At the same time, the interior lighting is dimmed slightly.

When the driver turns on the ignition, ambient lighting mode is activated. The interior lighting is switched off and discreet ambient lighting is turned on, with the settings (brightness and colour scheme) being selected by the user. When the key is removed from the ignition switch, all the interior lights come on at full brightness.

As the driver locks the car, the lights are turned off first for the rear seats, then for the passenger seat and finally for the driver’s seat. Only certain exterior lights which are controlled separately by the coming home function remain illuminated.

Controlling and customising the lights
The interior lighting in the Audi A8 is managed by a newly developed control unit, known as the ambient lighting module, and by the main lighting module. All the light functions are networked, so that they can be adjusted centrally via the multimedia interface.

The brightness of the ambient lighting can be adjusted for the entire interior or separately in four different zones. In addition, the driver can choose from three different colour schemes. The colours available are polar (bright white), ivory (off white) and ruby/polar (red/bright white), depending on whether the occupants want a cool (polar), pleasantly warm (ivory) or sporty (ruby/polar) ambience.

The light strips in the roof liner between the grab handles act as interior and ambient lights. Bertrandt designed the connector, the fibre optics and the two-part housing.

Trendsetter
New design requirements are constantly raising the bar for modern lighting technology. LEDs and fibre optics are under ongoing development. Improved fibre optic materials, more powerful LEDs and the use of the latest simulation software for designing and refining lighting elements are increasing the efficiency of the development process. Bertrandt’s contribution to a range of Audi projects in the form of the design, simulation and prototyping of fibre optic lights has enabled the company to become fully familiar with these trends. The expertise it has acquired in these areas has been put to good use in the case of the Audi A8. Bertrandt is currently working on another technology for the future: organic light-emitting diodes (OLEDs). In contrast to LEDs, which function as spot lights, OLEDs can provide uniform illumination for larger areas. This new technology gives light designers and developers more freedom to put their ideas into effect.

The new interior and ambient lighting of the Audi A8 demonstrates the future trends in interior lighting. The light sources are almost exclusively LEDs and offer end customers extensive customisation options. The integrated scenarios transform the lighting into an experience. Bertrandt is looking forward to continuing to provide Audi with lighting expertise.