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Brakes and wheels The brake system featured in the new Audi A3 appropriately matches the dynamic talents of the car: Four disc brakes varying in size depending on the engine ensure safe and reliable deceleration whenever required. The top-of-the-range 3.2 quattro even comes with a 17-inch brake system setting a new standard in this segment. On the front-wheel brakes this means disc diameter of no less than 345 millimetres or 13.6". The Audi A3 is also the pioneer in its class when it comes to operation of the brakes. Like the Audi S4 before it, this compact premium athlete now features a dual rate brake servo allowing very sensitive application of brake forces under normal conditions with a reinforcement ratio of 1:5. When the driver applies the brakes in an emergency, however, the brake servo, on sensing a pre-defined braking pressure, switches to a higher support factor of 1:8.5. An Electronic Stabilisation Program of the latest generation, ESP, ensures active safety reserves at all times. This wheel-slip control system comprises the following functions: the ABS anti-lock brake system, EBD Electronic Brake-force Distribution, ASR Anti-Slip Regulation, engine-drag-torque control MSR, the EDL Electronic Differential Lock, the hydraulic brake assist and the extended stabilisation braking system ESBS. The enhanced control algorithm in the electronic control unit now enables ESP to recognise potentially critical situations at an even earlier point in time, intervening preventively whenever necessary. With its self-learning capacity, ESP consistently monitors the car even under stable driving conditions, thus adjusting the intervention point to the current driving situation on the road. The result is an increase in both safety and comfort, ESP intervening much earlier in critical situations and avoiding unnecessary action whenever appropriate. The Attraction and Ambiente versions of the A3 come as standard on 16-inch wheels running on 205/55 R 16 tyres. On the Ambiente models the wheel rims themselves are made of cast aluminium. The high-performance Ambition versions of the A3 and the 3.2 V6 come with sports suspension and 17-inch cast aluminium wheels running on 225/45 tyres. This combination not only looks very dynamic, but also offers supreme driving qualities on both dry and wet roads. Both 16- and 17-inch wheels are available for driving in winter. And last but not least, all A3 are fitted as standard with the Tyre Mobility System, a run-flat spare tyre being available as an option. Body The new Audi A3 is a wonderful example of the many options and benefits offered by a modern steel bodyshell, combining superior stiffness - which also means excellent vibration comfort - with supreme resistance in a crash and efficient lightweight technology. This synthesis is made possible by the specific use of strong and extra-strong body panels, tailored blanks varying in width as well as the most advanced and sophisticated joining technologies. In all, the share of strong and extra-strong steel panels on the new A3 is no less than 62 per cent. Compared with the first generation of the Audi A3, the number of components has been significantly reduced especially on the floor assembly, the entire front area of the car now consisting of just one single unit. The big advantage, of course, is lower weight and extra rigidity all in one. And although the former A3 was most definitely one of the best cars in its class in terms of body strength and stiffness, the new model offers an overall improvement in dynamic flexural and torsional rigidity of approximately 20 per cent. Static torsional rigidity is up by an even more impressive 33 per cent. Excellent vibration comfort A high level of local and overall dynamic stiffness in the body of the car is essential to ensure superior vibration comfort. The objective is to keep vibration amplitudes to a minimum at all points of the car relevant to comfort such as the footwells, the area beneath the seats, and the area around the steering wheel. The body-in-white of the new A3 plays a significant role in achieving this goal. Cross-sections designed to cope with varying loads, profiles remaining consistent and unchanged throughout the body, and thoroughly optimised structure points connecting the various components all act together to provide an optimum all-round concept. Tailored blanks are used again on the body to guarantee efficient use of materials. Modern adhesive is also used in conjunction with welding spots and laser seams together with spot-welded connections to ensure firm and stiff connection of the individual components. No less than 3 metres of laser seams serve to connect the roof and the side frame alone. Integrated assembly components such as the hybrid front end, aluminium subframes and an aluminium cockpit support integrated in the overall structure of the body serve to enhance all-round body stiffness to an even higher level.
Stable structures for passive safety A high standard of occupant safety is one of the obvious goals in developing an Audi - this applies equally to head-on, side or rear-end collisions, as well as passenger safety in a rollover. The Euro-NCAP crash hitting a deformable barrier at 64 km/h and with 40 per cent overlap of the front end is an important criterion for determining the safety of a car in the most common type of accident, a head-on collision. The structure of the new Audi A3 is protected in such a case by a multi-chamber aluminium crossbar bumper system with deformation elements positioned slightly further back. Interacting with the longitudinal arms or "chassis legs", as they are often called, the bumpers absorb energy with maximum efficiency to relieve the load on the passenger cell and, in particular, the footwells. The aluminium subframe at the front of the car is bolted in position at six points, spreading out forces efficiently throughout the extra-strong floor and tunnel structure. Within the passenger compartment exact coordination of all restraint systems as well as kinematic action of the steering column and pedals keeps forces acting on the occupants to a minimum. Full-size frontal airbags for the driver and front passenger as well as belt tensioners and belt-force limiters reduce forces acting on the occupants' bodies in a head-on collision with maximum efficiency. Special padding on the steering column and in the footwells as well as the foot support and the upright accelerator pedal protect the driver's lower extremities, particularly his sensitive ankles and leg joints. In a collision from the side the occupants in the A3 benefit from the particularly strong and solid structure of the bodyshell. A homogeneous contour and cross-sectional design ensure the appropriate deformation kinematics, especially in the area of the B-pillar and side sill. The central sill profile, in turn, avoids any major deformation and, together with the extra-large seat crossbars, guarantees very good support particularly helpful under very substantial local loads, for example when hitting a pole. In the door area a hybrid carrier system consisting of an aluminium collision safety support with a bolted-on steel apron ensures additional safety. In a side-on collision the carrier system rests consistently on the side-sills, thus transmitting forces to the lower structure of the car with maximum efficiency. Inside the car, seat-integrated hip-thorax side airbags help to maintain a supreme standard of safety. The sideguard head airbag system is featured as standard in all new Audi A3 in Western Europe, covering almost the entire window area from the A- to the C-pillar and significantly reducing impact forces in the process. With the airbags being rapidly filled by a hybrid gas generator and maintaining their pressure consistently for a long period, passenger safety is ensured quickly and consistently, with an adequate safety potential also in secondary, follow-up collisions. Active headrests in the front seats reduce the risk in a rear-end collision. Activated mechanically, they move forward whenever required to cushion the occupant's head quickly and efficiently. A comprehensive crash detection system with no less than six satellite crash sensors on the B- and C-pillars and in the front-end support serve to activate the restraint systems with the same standard of efficiency. This ensures on-demand detection of accidents, with the occupants being efficiently protected by decelerating together with the car itself. Over and above these benefits, the crash sensors in the new Audi A3 offer additional safety in an accident by opening the central locking, switching on the hazard warning lights and interrupting the supply of fuel to the engine. The compact Audi is also protected with maximum efficiency from the effects of a head-on collision. Indeed, the Audi A3 already meets the requirements of future standards. This means that it safely resists an impact against a deformable barrier at up to 80 km/h and with at least 70 per cent overlap, the passenger cell and the fuel tank both remaining outside of the actual deformation area in such a collision. The entire rear structure of the car deforms specifically with the help of extra-large support arms, absorbing impact energy for extra safety. Low insurance premiums thanks to superior ease of repair Insurance premiums are a significant factor in the cost of ownership of any car. Precisely this is why the engineers developing the body of the Audi A3 sought from the start to give the bumper systems not only a superior protective effect in a collision, but also equally superior qualities in resisting minor damage and allowing ease of repair in minor collisions. The essential criterion considered by German insurers in determining their full coverage premiums is the 15 km/h model damage test - a test the Audi A3 has already passed with flying colours. The front bumper support is connected to the body in such a way that it will break clear of its mounting points in the event of a collision, thus providing longer deformation travel. And at the same time the bumper will jump off the side panel to avoid any damage to the wings of the car. As a result, the new A3 1.6 comes in Germany in the extremely low and inexpensive full coverage insurance category 13, thus offering lower premiums than any other model in the compact segment. Fine-tuning in the wind tunnel A longer wheelbase and wider track, the longer and wider body reduced in height, as well as wider tyres than on the former model: On account of these different dimensions, together with the new design of the car, the new-generation Audi A3 offers a completely new standard of streamlining and aerodynamic efficiency. The No 1 challenge in designing the car was to maintain the very good drag coefficient despite the larger frontal area. And the most significant improvements made for this purpose are the fine-tuning of the underfloor with its full panel extending from front to rear. Developing this kind of aerodynamic cover was of course the ideal task for Audi's wind tunnel in Ingolstadt, with the simulation of ground effect conditions provided by belts running beneath the car allowing very realistic assessment of air flow below. A spoiler fitted on the bottom of the front bumper serves to efficiently guide the flow of air entering the underfloor area. Spoilers on all four wheels, in turn, ensure an adequate flow of cooling air to the brake discs kept clean and free of dirt to the greatest possible extent. Two large underfloor covers around the middle of the car maintain a smooth flow of air with virtually no turbulence or air swirl. So-called heel plate spoilers at the rear end of the underfloor panel, finally, block off the flow of air beneath the car so efficiently that the air flow along the upper rear section changes favourably, preventing the flow of air from resting directly on the rear window and thus keeping this area clean, without the contamination so often seen here on a coupé or fastback. Detailed work was also conducted in the wind tunnel on the front end of the car with its air inlets - which is indeed all the more important, since the many different engines available in the A3 vary in their demand for cooling air. The successful result is the reduction of ornamental grilles used on the various models to just two different grille sections as opposed to five different variants on the first-generation A3. With its drag coefficient of just 0.33, the new A3 1.6 again offers advantages in terms of performance, driving dynamics and fuel economy. Audi's aeroacoustics specialists have also worked hard on the new car, the perception of noise obviously having a certain effect on the feeling of quality for the driver and his passengers. Two areas are indeed of particular significance in this context: the doors and the windscreen wipers, where annoying high-frequency vibrations are generated particularly often. Carefully conceived seals serve to avoid such vibration and noise around the doors, the sealing line on the front upper door frame being appropriately positioned to keep the base of the exterior mirror with its holes drilled into the body potentially causing noise outside of the actual door area. Conducting a long series of tests in the wind tunnel, Audi's aeroacoustics specialists have also optimised the design of the mirrors, the water drain rails and the aerial. Applying experience gained in developing the A4 and the A8, they have enlarged the radius of the front edge of the water drain rail in order to reduce the noise effect. High-tech improvements are also featured on the windscreen wipers, helping to minimise wind noise both with the wipers inactive and when in use. This is made possible by Audi's new flat wiper technology which, without making any concessions in wiper performance even at high speeds, helps to reduce the noise level and improve the frequency curve in comparison with conventional windscreen wipers. This screen wiper technology benefits in particular from the carefully conceived flow of air around the wiper arm and blade with its integrated spoiler. The wiper arm, in turn, is extremely stiff and sturdy, thus exerting additional downforces on the wiper blade. | ||||||||
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