Digital transformer
The Mercedes-Benz “Concept IAA” (Intelligent Aerodynamic Automobile) is two cars in one: an aerodynamics world champion with a Cd value of 0.19 and a four-door coupé embodying irresistible design.
The study, which is celebrating its world premiere at the Frankfurt International Motor Show, switches automatically from design mode to aerodynamic mode when the vehicle reaches a speed of 80 km/h, whereby numerous aerodynamics measures alter the shape of the vehicle.
Inside, the “Concept IAA” continues the design line of the S-Class and S-Class Coupé, offers new touch-based functions and provides an idea of what the interior of a business saloon might look like in the near future.
At the touch of a button, or automatically on reaching a speed of 80 km/h, the Mercedes-Benz “Concept IAA” (Intelligent Aerodynamic Automobile) performs a fascinating transformation in which the captivatingly beautiful four-door coupé turns into an aerodynamics world champion: eight segments extend at the rear, increasing its length by up to 390 millimetres; front flaps in the front bumper extend by 25 mm to the front and 20 mm to the rear, improving the air flow around the front end and the front wheel arches; the Active Rims alter their cupping from 55 mm to zero; and the louvre in the front bumper moves 60 mm to the rear, improving the underbody air flow.
The ‘Concept IAA’ applies intelligent innovations to resolve the conflicting aims of functionality and aesthetics and shows that we still have plenty of ideas on how to achieve further improvements in efficiency,” says Prof. Dr Thomas Weber, Member of the Daimler Board of Management responsible for Group Research and Head of Mercedes-Benz Cars Development.
Equally, the “Concept IAA” exemplifies the fundamental technological changes which are taking place in the automobile industry.
The primary driving force behind this process of change is digitisation – commonly referred to in a business context as “Industry 4.0”.
For Mercedes-Benz, a continuous digital process chain from research and development through production to marketing and sales, logistics and the service area is already becoming reality.
The design and aerodynamic shaping of the “Concept IAA” would not have been possible without the systematic digital networking of different specialist departments.
The designers have employed the latest algorithmic design methods to handle the complex geometric design. The individually adapted software enables dynamic design in three-dimensional space.
This dynamic modelling makes it possible to display and model different states simultaneously. The resultant highly complex geometries were turned into reality with the aid of innovative production technologies (rapid prototyping).
The world-beating aerodynamics were developed in parallel with the aid of numeric flow simulation.
In around one million CPU hours, the aerodynamics experts from Mercedes-Benz simulated the flow characteristics, calculating some 300 variants. This roughly corresponds to the scope of work involved in developing a production model.
The “Concept IAA” also offers a look into the future in areas which are not apparent at first glance. The study features Car-to-X technology, for example, which enables the study to communicate with other vehicles or other sources of information.
This represents a major advance in helping to avoid accidents, as obstacles or events which are not visible to the vehicle itself can be detected – the “Concept IAA” is able to look around the corner, as it were.
With this and its interior and operating concept, the “Concept IAA” also offers a foretaste of the business saloon of the near future.
Exterior design: sensual purity and innovative aerodynamics
With its dynamic basic shape (“drop shape”), elegantly purist overall design and aerodynamic innovations, the four-door “Concept IAA” Coupé Saloon is a symbiosis of design and aerodynamics.
The vehicle interprets classic sports car proportions in a modern vein: the long bonnet flows aerodynamically into the compact, set-back greenhouse, whose roof slopes down elegantly towards the rear, ending in an airflow break-away edge.
The vehicle’s elegant side view combines a purist, long basic volume with highly pronounced wheel arches. The sporty, minimalist front of the show car boasts a striking “shark nose” profile.
Like the front, the show car’s rear end also presents a clear-cut and purist appearance. As on the front grille, horizontal louvres lend structure to the shape of the rear end.
An illuminated ring running around the rear end adds the finishing touch to the high-tech appearance.
“The ‘Concept IAA’ continues our series of visionary concept cars,” explains Gorden Wagener, Head of Design at Daimler AG.
“The symbiosis of alluring forms showcasing intelligent aerodynamics is an expression of our unique Mercedes-Benz design philosophy.”
The interior: touch-based operating philosophy
The interior of the “Concept IAA” combines stylish sportiness with modern luxury. The interior continues the design line of the S-Class and S-Class Coupé while providing an idea of what the interior of a business saloon might look like in the near future.
The choice of colours and materials conjures up extrovert contrasts between anthracite and white as well as between aluminium and cut glass.
Elegantly curved forms, flowing lines, carefully chosen high-quality materials and the touch-based operating philosophy provide for a high level of functionality.
The two-spoke steering wheel is a progressive further development of the Mercedes-Benz steering wheel philosophy. The open structure of its horizontal spokes is highly intricate in design, as a manifestation of intelligent and elegant lightweight construction.
The steering wheel also incorporates touch-based operating functions, offering great functionality in the most compact dimensions as a study in perfect ergonomics: OFN (Optical Finger Navigation) buttons, embedded in the clusters in a similar hovering manner as the touchpad in the centre console, enable the driver to scroll through the instrument cluster menus.
The OFN button on the left controls the left-hand display, while the button on the right controls the right-hand display. In this way, the “hands on the wheel, eyes on the road” operating philosophy which has been applied by Mercedes-Benz for many years now is implemented in a manner which is at once brilliantly simple and uncompromising.
“Captivatingly sporty lines, fascinating technical solutions: the ‘Concept IAA’ symbolises the emotional core of Mercedes-Benz: The best or nothing.
And it shows in a host of details what our customers can look forward to in future production models,” says Ola Källenius, Member of the Board of Management of Daimler AG, Mercedes-Benz Cars Marketing & Sales, summing up the visionary concept.
The “Concept IAA” is 5040 millimetres long (5430 mm in aerodynamic mode), 1995 mm wide and 1305 mm high. Its wheelbase measures 2975 mm, and the front/rear track widths are 1710 and 1770 mm respectively.
The concept car is powered by a petrol/electric plug-in hybrid drive with a total output of 205 kW (279 hp). This provides it with a top speed of 250 km/h (electronically limited).
CO2 emissions and electric range depend on the mode in which the vehicle is tested: in aerodynamic mode the “Concept IAA” manages an all-electric range of 66 kilometres and emits 28 g CO2 per km. In design mode the range stands at
62 km and CO2 emissions at 31 g per km.
As urban driving is accorded a two-thirds weighting in the current New European Driving Cycle (NEDC), the advantage of aerodynamic mode is not revealed as clearly in this test as in real-life driving.
Real-life fuel savings are all the greater, however – in keeping with Mercedes-Benz’s customer-oriented “Real Life Efficiency” philosophy.
The “Concept IAA” show car forms part of a long line of aerodynamically perfected vehicles from Mercedes-Benz. With a dimensional concept that makes it suitable for everyday use, this four-seater attains a Cd value of 0.19, assuring it of a place in the gallery of record-breaking and racing vehicles such as the Mercedes-Benz W 25 record-breaker of the 1936 season.
At present the models from Mercedes-Benz occupy the top position for aerodynamics in practically every vehicle segment. In 2013 the Mercedes-Benz CLA attained a Cd figure of 0.22 – marking a new all-time low both within the Mercedes-Benz model portfolio and amongst all series production cars.
The Mercedes-Benz management team on the “Concept IAA”
“Fascinating and technically sophisticated”
“Fascinating and technically sophisticated cars form the core of Mercedes-Benz. The ‘Concept IAA’ applies intelligent innovations to resolve the conflicting aims of functionality and aesthetics and shows that we still have plenty of ideas on how to achieve further improvements in efficiency.”
Thomas Weber, Member of the Daimler Board of Management,
Group Research and Mercedes-Benz Cars Development
“The ‘Concept IAA’ continues our series of visionary concept cars,” explains Gorden Wagener, Head of Design at Daimler AG. “The symbiosis of alluring forms showcasing intelligent aerodynamics is an expression of our unique Mercedes-Benz design philosophy.”
Gorden Wagener, Head of Design at Daimler AG
“Captivatingly sporty lines, fascinating technical solutions: the ‘Concept IAA’ symbolises the emotional core of Mercedes-Benz: The best or nothing. And it shows in a host of details what our customers can look forward to in future production models.
Ola Källenius, Member of the Board of Management of Daimler AG, Mercedes-Benz Cars Marketing & Sales
The exterior design
Sensual purity and innovative aerodynamics
Sensually shaped surfaces and volumes providing stimulating contrasts with functional high-tech details: the “Concept IAA” shows how intelligence and beauty can be combined to form an exciting whole.
With its dynamic basic shape (“drop shape”), elegantly purist overall design and aerodynamic innovations, the four-door “Concept IAA” Coupé Saloon is a symbiosis of design and aerodynamics.
The vehicle interprets classic sports car proportions in a modern vein: the long bonnet flows aerodynamically into the compact, set-back greenhouse, whose roof slopes down elegantly towards the rear, ending in an airflow break-away edge.
A short overhang at the front and a longer one at the rear emphasize the vehicle’s dynamic character, as does the cab tapering towards the rear.
The cab is supported on the muscular shoulders at the sides and merges into the powerfully shaped rear fenders.
The sporty, minimalist front of the show car boasts a striking “shark nose” profile and a flat and wide radiator grille opening.
The design of the horizontal louvres in the opening is continued in the LED headlamps. The seamless transition of the louvres into horizontal headlamp elements underscores the vehicles purist and powerful yet sensual and technoid appearance.
The louvres open and close from the outside inwards according to the required levels of cooling air. The spoiler lip moves 60 mm to the rear when the vehicle reaches a speed of 80 km/h.
The vertical aero flaps look spectacular in the front bumper in front of the wheels. They can extend to the sides for an ideal air flow around the front wheels (see Aerodynamics section).
During extension, that is, when switching over to aerodynamic mode, the edges of the wings light up in blue. Cameras in the side air outlets behind the front wheel arches monitor goings-on to the rear.
Their images are projected onto the split-screen rear view mirror in the interior. This makes exterior mirrors superfluous.
The vehicle’s elegant side view combines a purist, long basic volume with highly pronounced wheel arches and precisely executed details such as joints or air intakes and outlets.
The side windows have been printed in the body colour (alubeam) by means of a screen printing process. This reduces the amount of sunlight entering the interior while at the same time lending the vehicle the appearance of a sensual, silver high-tech sculpture.
As the vehicle speed increases, the Active Rims are transformed by centrifugal forces from sportily sculptured wheels into flat, supremely aerodynamic disk wheels.
In this way, they contribute to the vehicle’s overall performance not only on an aesthetic level but in functional terms, too (see Aerodynamics section for further details).
The designers have dispensed with traditional door openers. Instead, pulsating blue LEDs indicate where the touchpad to open the doors is located. A tap of the finger suffices to open the doors.
Like the front, the rear end of the “Concept IAA” also presents a clear-cut and purist appearance. At higher vehicle speeds, two-dimensional elements are extended within the air flow break-away edge in aerodynamic mode, forming a ring-shaped rear extension.
This causes the air flow to hug the vehicle for longer, eliminating unpleasant turbulence. The vehicle’s drop-shaped overall volume is further improved in this way (see Aerodynamics section).
As on the front grille, horizontal louvres lend structure to the shape of the rear end. An illuminated ring running around the rear end adds the finishing touch to the high-tech appearance.
It is not visible in aerodynamic mode, however – shell-shaped LED lamps then assume the rear lighting functions. The tail lights are a stand-out feature, with a look that is evocative of stardust or the glow of a jet engine.
The “stardust look” lights will make their debut in a series-produced model at the beginning of 2016.
The interior
Flowing lines, high-quality materials and touch-based operation
The interior of the “Concept IAA” combines stylish sportiness with modern luxury. The interior continues the design line of the S-Class and S-Class Coupé while providing an idea of what the interior of a business saloon might look like in the near future.
Attractively curved forms, flowing lines, carefully chosen high-quality materials and the touch-based operating philosophy provide for a high level of functionality.
The designers have adopted a holistic approach to the material and colour concept: the interior cites the exterior, with white and anthracite predominating as elegantly high-tech basic colours.
Other features linking interior and exterior are colour highlights in the colour blue, which stands for efficiency, graphic patterns such as the engraved lines in the trim elements, which suggest air flows, and the dynamic high-tech perforations which are to be found both on the wheel rims (in design mode), on the seat side bolsters and in the door panels above the loudspeakers.
The entire floor of the show car is covered in leather, over which dynamic lines run like a flow of energy.
The instrument panel seamlessly merges into the doors in a wrap-around design. The curved trim element emphasizes the horizontal.
The wavelike motion continues in the door panels. The trim element is all-aluminium, with milled lines alluding to the aerodynamically optimised exterior.
The eight air vents have been produced by Swarovski on commission by Mercedes-Benz as a work of art in glass.
This authentic material offers an unparalleled depth effect which endows the vents with a rich variety of reflections. They are showcased by ambient lighting in a thrilling combination of blue and red.
A functional and aesthetic trilogy: the display and operating concept
The triad of steering wheel, instruments and head unit in the “Concept IAA” forms an aesthetic, classy whole which has been adopted from the Concept S-Class Coupé (IAA 2013) and subjected to further refinement.
The basic colours of the highly aesthetic and clear interface design are based on the blue ambient light and create a harmonious, stylish link between interior lighting and user interface.
Instrument and head unit become an information landscape, combining displays embodying high-tech clarity with cutting-edge, flowing design.
The instrument cluster consists of two 12.3-inch screens positioned alongside one another. The displays are flush-mounted behind glass.
The glass features ground edges and an all-round aluminium chamfer. The glass elements are all bonded – this entails filling the minimal gap between front glass and film with a transparent adhesive in the production process, which provides for substantially improved optical quality and more robust screens.
The centre console features a trim element consisting of three-dimensionally curved glass in which a touch display is integrated.
The air conditioning and seat adjustment functions are operated here, and there are entry buttons for the different operating menus.
The aerodynamic exterior elements can be controlled in a new menu. Hovering over a base directly under this is the touchpad to control the menus of the head unit.
The two-spoke steering wheel is a progressive further development of the Mercedes-Benz steering wheel philosophy. The open structure of its horizontal spokes is highly intricate in design, as a manifestation of intelligent and elegant lightweight construction.
The steering wheel also incorporates touch-based operating functions, offering great functionality in the most compact dimensions as a study in perfect ergonomics: OFN (Optical Finger Navigation) buttons, embedded in the clusters in a similar hovering manner as the touchpad in the centre console, enable the driver to scroll through the instrument cluster menus.
The OFN button on the left controls the left-hand display, while the button on the right controls the right-hand display. In this way, the “hands on the wheel, eyes on the road” operating philosophy which has been applied by Mercedes-Benz for many years now is implemented in a manner which is at once brilliantly simple and uncompromising.
Sculptural lines and extremely light: the seats
The torso-shaped seats have a highly sculptural appearance, their lightweight design underscoring the emphasis on efficiency which is integral to the “Concept IAA”.
The seat shells consist of brushed aluminium. The thin seat bases are covered in white leather. The brand’s signature vertical fluting suggests dynamism.
The side bolsters additionally feature elaborate perforations with a metallic effect. In addition to being perfectly matched to the seat upholstery layout, the CNC perforation also underscores the shape of the seats by virtue of the dynamic orientation of the punched holes.
This kinetic effect of the perforation is achieved by a fading of the hole sizes, which is further emphasised by the metallic reverse side presenting a very high-tech look.
The choice of colours and materials conjures up extrovert contrasts between anthracite and white and between aluminium and a cut-glass look.
White has deliberately been chosen for the entire roof lining. The bright, radiant colour exudes clarity. Blue is to be found in the ambient light and the piping on the leather, for example.
Aerodynamics
New Cd world record achieved through active transformation
Two cars in one – on reaching a speed of 80 km/h, the “Concept IAA” switches automatically from design mode to aerodynamic mode, whereupon numerous active aerodynamic measures alter its appearance.
As a result of this transformation, the Cd value improves from 0.25 to 0.19 – a new world record for a four-door four-seater. The frontal area totals 2.16 m2.
The active aerodynamic measures at a glance:
- The front flaps in the front bumper in front of the wheel arches move outwards by 25 millimetres and 20 millimetres to the rear, up to the rear edge of the wheel crescent. This substantially improves the inflow of air to the wheels and the flow of air over the front wheel arches.
- The louvre in the front bumper moves 60 millimetres to the rear, improving the flow of air towards the underbody.
- The Active Rims alter their cupping with the aid of centrifugal force from 55 to 0 millimetres, transforming them from sporty 5-spoke wheels into flat disc wheels offering exemplary aerodynamic characteristics.
- In conjunction with the diffuser, the rear extension which is extendable by up to 390 millimetres ensures that the air flow hugs the vehicle more closely and that the after-flow zone behind the vehicle’s rear end is substantially smaller. This results in a considerable reduction in drag. The rear extension in “boat tail” design consists of eight segments produced in CFRP in a sandwich structure which close to form a ring.
As a result of the streamlined design, the downward slope of the roof line begins further towards the front. In order to offer the rear passengers sufficient headroom, the roof thus incorporates two rises over the rear seats.
Numerous other aerodynamic optimisations contribute to the vehicle’s excellent performance in the wind tunnel. These include windows which fit flush on the outside, the omission of door openers and lowering of the chassis, resulting in a ground clearance of only 100 millimetres.
The underbody panelling comprises partial covering of the centre tunnel, with perforation of the panelling here to allow cooling of the exhaust system, and extensive cladding on the rear axle.
As on the new C-Class, an adjustable radiator grille shutter (air panel) helps to reduce drag. When only low cooling requirements apply, the concentric louvres in the radiator grille are closed in order to prevent air from entering into the engine compartment.
Basic ventilation then takes place primarily via the Mercedes star and the cooling air opening in the bumper.
The “Concept IAA” aerodynamics world champion was initially evolved with the aid of numeric flow simulation. In around one million CPU hours, the aerodynamics experts from Mercedes-Benz simulated the flow characteristics, calculating some 300 variants.
This roughly corresponds to the scope of work involved in developing a production model. Fine tuning then took place in the wind tunnel in Sindelfingen – another parallel with series production development.
The heritage
Aerodynamically perfected record-breaking cars
The “Concept IAA” forms part of a long line of aerodynamically perfected passenger cars, racing cars and record-breaking vehicles from Mercedes-Benz, which began in 1909 and achieved a spectacular milestone in the Olympics year of 1936.
With a dimensional concept that makes it suitable for everyday use, this four-seater attains a Cd value of 0.19, assuring it of a place in the gallery of record-breaking and racing vehicles described below – although the other cited examples were able to exploit substantially more extreme dimensional concepts without any consideration for spaciousness and comfort.
The Mercedes-Benz W 25 record-breaking car of the 1936 season featured a chassis bearing a fully streamlined body for the first time which also included the wheels and the underside of the car.
In the wind tunnel at the Zeppelin plant in Friedrichshafen, the experts analysed the body’s air flow characteristics and optimised its aerodynamics.
These efforts yielded a Cd value of 0.235, a world speed record and three international class records. Rudolf Caracciola clocked up a top speed of 372.1 km/h in the 419 kW (570 hp) record-breaking car.
On 28 January 1930, the following project, the Mercedes-Benz W 125 record-breaking car, set a new speed record on public roads which stands right up to the present day, with Rudolf Caracciola having reached a speed of 432.7 km/h.
The record-breaking version of the W 125 Silver Arrow was primed for its special purpose in the wind tunnel of the German test facility for aviation applications in Berlin-Adlershof.
The flat, fully panelled body with a wedge-shaped rear end achieved a sensational Cd value of 0.157. A radically scaled-down air intake at the front was a further contributory factor here.
This meant that the record-breaking car only breathed in the amount of air that the 5.6-litre V12 engine with an output of 541 kW (736 hp) required in order to operate.
The engine cooling system did not use fresh air at all. Instead, the radiator was encased in a box filled with 500 litres of ice and water, which at the same time reduced lift at the front axle.
The 8.24 metre-long T 80 three-axle record-breaking vehicle from 1939 was an even more radical proposition. With this car, Mercedes-Benz aimed to break the world speed record which had been pushed up to 595 km/h on a salt lake in Utah, USA in 1939.
The powerful vehicle was to be driven by an 807-kilogram V12 aircraft engine generating a massive 2574 kW (3500 hp) of power from a displacement of 44.5 litres.
The T 80 was never deployed, however, due to the outbreak of the Second World War.
For the motorway: 540 K Streamliner from 1938
The acquired aerodynamic findings were applied not only for record-breaking attempts, however, but also on the road.
The Mercedes-Benz 540 K Streamliner built in 1938 crowned the development of aerodynamically optimised
Mercedes-Benz vehicles in the 1930s.
The one-off model based on the Stuttgart-based brand’s sporty top-of-the-range model set both technical and aesthetic standards.
In the light of ever-faster travelling speeds made possible by the swift pace of technological progress and the growing network of fast roads, the aerodynamics of powerful passenger cars acquired increasing importance with regard to efficiency aspects in particular.
With the flowing lines and the low profile of its aluminium body, the minimised drag sources on its surfaces and the panelled underbody, the Streamliner applied the findings of research in exemplary manner – with a remarkably low drag coefficient of Cd = 0.36.
Mercedes-Benz 2.5-litre streamlined racing car W 196 R, 1954
The streamlined design of the Silver Arrows became a global talking point once again in 1954 with the arrival of the totally new W 196 R racing car.
The aerodynamically optimised streamlined version, which was still allowed in Formula 1 at the time, was the first to be built for the 1954, because the opening race in Reims/France permitted very high speeds.
A second variant with open wheels followed four weeks later. Mercedes-Benz’s return to motor racing ended in spectacular style, with Juan Manuel Fangio and Karl Kling achieving a one-two win.
In the improved version of the streamlined car he also won the last race in which the W 196 R competed – the 1955 Italian Grand Prix. This sealed Fangio’s second world championship title driving the Silver Arrows.
Mercedes-Benz C 111-III record-breaking car, 1978
From 1969 on, Mercedes-Benz built a series of experimental and record-breaking vehicles with the internal designation C 111.
The C 111-III diesel record-breaking car from 1978 underwent systematic aerodynamic optimisation. The vehicle was slimmer than its predecessor, with a longer wheelbase, fully faired wheels and a long rear end.
This design lowered the Cd value of the C 111 to 0.183. On record-breaking runs at the high-speed circuit in Nardò in southern Italy, the vehicle provided an impressive demonstration of efficiency, with a five-cylinder in-line turbodiesel engine rated at 169 kW (230 hp) powering the streamlined car to speeds well beyond 300 km/h.
The nine world records achieved with the C 111-III include an average speed of 319 km/h over a distance of 1000 miles (1609 km).
The series production cars from Mercedes-Benz also set new benchmarks in aerodynamics on a regular basis.
Examples of the long-standing traditions which also apply in this area are the S-Class of the 126 model series which was presented in 1979 with a Cd value of 0.36, the saloons of the 124 model series which were introduced in 1984 with a Cd figure of 0.29 and the S-Class saloon (W 220) launched in 1998 with a Cd value of 0.27.
At present the models from Mercedes-Benz occupy the top position for aerodynamics in practically every vehicle segment.
In 2013 the Mercedes-Benz CLA attained a Cd figure of 0.22 – marking a new all-time low both within the Mercedes-Benz model portfolio and amongst all series production cars.
