Dynamic and exclusive: the design
The Audi A4 Cabriolet is a vehicle whose temperament and unique quality are immediately obvious at first glance: the flat front end, the subtle wedge shape and the powerfully contoured tail with visible tailpipes are clear indications of the sporting prowess that it has inherited from its designers.
With its powerful proportions and the unique, overtly dynamic shape of the front and tail ends, the new Cabriolet retains an extremely individual aura. The windscreen frame with its aluminium finish and the aluminium strips along the waistline additionally underline this distinctive design.
The distinct, round wheel arches and the basic line of the silhouette are reminiscent of the characteristic design features of the current A4 series. The Cabriolet's design is also characterised by a scrupulously economical approach. No swage lines or edges interfere with the dominant flat, taut surfaces and expansive arches. The result is an unaccustomed harmony of opposites: tranquillity and forward urge, geometric precision and palpable emotion.
The double radiator grille with chrome surround and the flat headlights with three-tube design behind a clear-glass cover indicate that the Cabriolet is a member of the A4 model family, yet still have their very own aura.
The geometry of the joins is mapped out with exactitude, as if with a single stroke of the pen. Here, the body join has been elevated to the status of a deliberately placed structural feature on a large-surface sculpture, instead of a mere line of contact between two body sections. Vertical joins connect the car's underbody with the headlights; the bumpers genuinely seem to be supporting the lighting units.
When open the hood is fully retracted and nothing interferes with the characteristic shoulder line which gives the vehicle body a smooth edge. But even with the hood closed, the dynamism and harmony of the silhouette are preserved. The wide arch of the roof's outline, without any visible ridges created by the linkage, accentuates the body's flat proportions and the subtle wedge shape of the unit as a whole.
The harmonious tail-end unit benefits from a new aerial system for radio, telephone and navigation system that is integrated into the luggage compartment lid, away from view.
The outstanding material quality and finish of the Cabriolet interior are typical of Audi. The interior design, perfectly matched to the styling of the exterior, plays a significant part in giving the entire Audi A4 Cabriolet an elegant overall appearance.
Its distinctly sporty driving area is carried by the striking centre console. Round air vents accentuate the overall dynamic character. In this way the interior of the Cabriolet is also kept deliberately distinct from that of the other A4 models, consequently demonstrating its exclusiveness.
The body: class benchmark for vibrational comfort
From the very outset, Audi's body specialists sought to create a structure that would represent the optimum in terms of both static and dynamic rigidity, and would be as close as possible to the characteristic of the saloon. Potential that enhances both the car's dynamic performance and its vibrational comfort. As far as combining these two qualities is concerned, the designers' objective was therefore as follows: the Audi A4 Cabriolet should set nothing less than the class benchmark.
The rigidity of the A4 Cabriolet body provides the ideal basis for unspoilt driving pleasure. The best measure of this is the static torsional rigidity of the bodyshell: it is more than twice as rigid as its predecessor - a quantum leap.
Measures designed to increase strength and rigidity also affect the choice of material grades and joining techniques. For instance, high-strength and ultra-high-strength panels account for more than fifty percent of the bodyshell's weight. Optimised wall thickness in conjunction with improved-quality weld points help to boost the structural durability of the body significantly.
The lower rigidity that is inevitable on a convertible compared with vehicles with a permanent roof could be compensated for on the Audi A4 Cabriolet above all by an optimised bodyshell structure. The body is in addition reinforced by a rigid bolted-on subframe at the front, with additional diagonal struts at the front and rear.
Countless different measures - and plenty of detailed optimisations - were necessary to achieve the required result. Overall tuning therefore took place for the first time before the first body prototypes were built: the basis for the efficiency of the experimental vehicle tuning was created during computer simulation.
In this phase the focus was not only on the structure of the body itself, but also on interaction with suspension and assembly movements.
The result of these development processes can be felt: the A4 Cabriolet remains unshakeable on roads of all kinds. Passengers are not troubled unnecessarily by either high or low-frequency vibrations.
What is amazing is that even the distinctly sporty overall tuning of the suspension is fully in accord with a high level of ride comfort.
Even driving pleasure benefits from body rigidity because the direct steering enables the A4 Cabriolet to be guided extremely accurately around corners. This is made possible by the special steering column connection that takes account of the vibrational behaviour that is specific to convertibles. The steering bracket is additionally supported, the module cross member is connected to the windscreen cross member - measures that play a decisive role in reducing vibrations at the steering wheel to a minimum.
Crash rigidity: of saloon standard
The A-post of the Audi A4 Cabriolet - which plays a particularly vital part in a roll-over - is reinforced ultra-efficiently. High-strength reinforcing tubes and the generally optimised design of the posts assure the desired properties.
Sills with an optimised thickness and cross-section boost the occupant cell's strength and optimise occupant protection. High-strength tubes are also used in the seat structure, as a means of enhancing occupant safety in the event of a lateral collision.
The doors, too, perform a very special safety function on this model; their mere dimensions highlight the differences compared with the smaller doors on the four-door A4 saloon and Avant models. In conjunction with the structural reinforcements in the sill and a cross reinforcement of the body beneath the rear seat bench, special impact members in the doors ensure the highest level of safety.
This guarantees that crash safety matches the exceptionally high standard set by the A4 saloon, even in a side pole impact.
At the car's rear end, the double rear wall improves the rigidity of the body. Occupant protection benefits from the standard roll-over protection system that is subtly integrated into the double rear wall.
The objective of Audi's developers was to create a passive safety concept that is on a par with that of the A4 saloon. The latter model has already demonstrated in impressive style just how effective its safety system is in several crash tests, including the Euro NCAP test for which it was awarded four stars.
The comprehensive safety package contains seat belts with belt-force limiter and belt tensioner for all passengers, together with full-size front and side airbags. The side airbags integrated into the front seats are designed to protect the head and thorax.
An active roll-over protection system provides additional safety if the car overturns. In this case, two protective bars, controlled by sensors, are triggered behind the rear passengers within milliseconds. Together with the extremely rigid windscreen frame, they help to preserve survival space for all occupants if the car turns over.
The standard Electronic Stability Program ESP with hydraulic brake assist provides for maximum active safety.