2007 Audi A6 Allroad

Transmision

The manual versions of the new Audi A6 allroad quattro – the 3.2 FSI and the 3.0 TDI – come with the ML generation of transmissions, the initials ML identifying them as "manual/longitudinal". This transmission with its sporty, close ratios offers short, crisp and supremely smooth gearshifts. A special mount for the selector forks effectively isolates the gear lever from driveline vibrations, while a raft of further measures raise overall efficiency by reducing internal friction.

The 6-speed tiptronic automatic transmission is available for all of the engines in the Audi A6 allroad quattro range, and is even fitted as standard on the 2.7 V6 TDI and 4.2 V8 FSI models. This transmission converts the engines’ power potential into a matchless blend of dynamic performance and delightful ease of use. Compared with its five-speed predecessor, the new six-speed transmission is 8 kilograms lighter with an overall weight of just 120 kilograms.

Again compared with the previous five-speed automatic transmission, the gear ratio spread has widened by 22 percent. This means sharper acceleration in the lower gears as well as a clear reduction in engine speed, and consequently a reduction in both noise level and fuel consumption, at high speeds.

The tiptronic control bears the name DSP (dynamic shift program). The lightning-fast gear changes and flexible gearshift strategy add sporting flair, as does the double-declutching initiated by the engine management during downshifts. With the selector lever in position D and when the S sport program is engaged, the electronics are programmed to respond to parameters such as lateral and longitudinal acceleration as well as to movement of the accelerator pedal. This helps to prevent any unwanted upshifts when cornering.

The quattro permanent four-wheel drive system, a standard feature common to all of the A6 allroad quattro models, is the very technology that has secured Audi its decisive status as technological leader for over quarter of a century now. quattro transforms the motoring experience, ensuring sure-footed traction and cornering and serving as a solid basis for dynamic handling and an extremely high degree of directional stability in all weathers.

At the heart of the quattro four-wheel drive in the new A6 allroad quattro is once again a self-locking centre differential. Operation of the differential is purely mechanical, meaning response is instantaneous. Its locking action is only prompted when the throttle is open; differences in rotational speed are tolerated when the brakes are applied and when cornering. Power is generally split 50:50 between the front and rear axles but, if necessary, up to 75 per cent of drive torque can be diverted to either axle.

Body

Despite its imposing dimensions, the new Audi A6 allroad quattro is nevertheless significantly smaller than the Audi Q7 performance SUV. It measures 4,934 millimetres long, 1,862 mm wide and, depending on the setting of the standard adaptive air suspension, between 1,459 and 1,519 mm high.

Compared with its predecessor, the new model is noticeably larger, with an extra 124 mm of length and 10 mm of width. The new A6 allroad quattro is available exclusively in Avant guise.

Torsional rigidity has been boosted by over 34 percent – an increase that bears clear testimony to the diligent work carried out by the Audi engineers. This extra strength makes its presence felt in terms of both superior vibration comfort and driving dynamics. The minimised vibration amplitudes are one of the key factors behind the excellent interior acoustics of the new A6 allroad quattro.

The systematic use of high-strength and ultra-high-strength sheet steel has made it possible to reinforce the structural components that are essential for ensuring a high level of stability. The inclusion of lightweight aluminium components such as panels and extruded profiles, on the other hand, has helped to save a considerable amount of weight. The A6 allroad quattro 3.2 FSI, for example, tips the scales at just 1,760 kilograms.

As on the predecessor, sheet aluminium proved to be the ideal material for the bonnet and front wings. Aluminium can also be used, however, on structural components that are subject to only moderate loads, such as the front panel of the radiator tank. The extruded aluminium profiles that have been added to the side sills help to reinforce the passenger cell.

The front roof frame has a hybrid structure, made from a combination of steel and plastic.

Tailored blanks, which are plates with varying wall thickness, or the closely related tailored rolled blanks are used at points subject to particularly high loads, such as the suspension strut cross-members or the front longitudinal members.

The various components are connected to one another using a range of different techniques: apart from conventional spot welding, rivets, spot welding combined with bonding, laser welding and soldering as well as MIG welding help to produce a lasting, solid connection. Each technology corresponds to the exact requirements at the point it is used.

One of Audi’s fundamental objectives in developing every model is to make the passenger cell extremely rigid. After all, this is the basic structure serving as the foundation for all of the car’s restraint systems and their protective effect.

One of the most important aspects to consider when designing this cell is behaviour in a frontal impact, as this is by far the most common type of impact in accident statistics.

This presents the body development engineers with two main tasks: first, to convert kinetic energy into deformation energy absorbed by body components and secondly, to ensure that this energy does not even reach the passenger cell, which must be made as robust as possible.

In a frontal crash, intelligent up-front sensors behind the radiator grille interact with other sensors and control units, before alerting the central control unit that the car has been involved in an impact within just a few thousandths of a second. The belt tensioners are then ignited just a few milliseconds later in order to minimise any possible belt slack. Once the loads acting on the belts have reached a certain limit, a belt force limiter feeds out additional belt length, allowing the occupants to "fall" into the airbag once it has inflated.

The full-size front airbags are activated in two stages: in the first stage – activated in low-speed impacts – the forces acting on the occupants are kept at a low level. At higher speeds, the second stage is triggered in order to utilise the full safety potential of the front airbags.

The particular position chosen for numerous elements, such as the air conditioning, control units, the ignition lock and key, is also an integral part of the car’s safety concept. All hard components have been moved away from critical impact areas where they might harm the occupants; other areas such as the footwells are cushioned by extensive padding.

The safety steering column comes with a double telescoping function, in other words it is – like the pedals – isolated from any intrusions from the front end of the car. A force limiter at the steering column mounting additionally ensures that the steering column will yield in response to impact with the driver’s chest, causing the steering wheel to move down to prevent injury.

In a frontal crash at low speed, there is no need for the airbags to be triggered. In such cases, all of the energy is absorbed by the bumper system, avoiding the need for expensive repairs to the welded body structure behind. Thanks to the precise deformation of the bumper, even the wings remain unharmed in a head-on collision at 15 km/h. Clearly, these are features that insurance companies welcome and duly reward with a particularly favourable insurance premium.

Unlike the front end of the car, there is only minimal deformation travel available at the side for absorbing energy. Only a particularly high degree of strength in this area can protect the occupants: this is precisely why the flanks of the new Audi A6 allroad quattro have a high-strength structure made primarily from dual-phase steels which offer outstanding rigidity and protection against excessive loads.

In the side sill, an extruded aluminium profile ensures effective absorption of energy. Within the doors, tailored blank inner panels combine with reinforcements at lower window edge and sill level plus an aluminium impact beam to offer substantial resistance to deformation.

Several beams arranged perpendicular to the direction of travel likewise serve to stabilise the passenger cell, while two high-strength steel pipes also installed laterally in the front seats help to keep the occupants’ survival space intact. High-strength reinforcements extending far into the roof area serve to protect the occupants if the vehicle rolls over.

In a collision from the side, the occupants are protected by side airbags fitted as standard at the front (optionally available at the rear) and the head airbag system known as sideguard. The latter covers almost the entire side window area. Hybrid gas generators inflate the airbags in an instant and the pressure is furthermore maintained for a longer period, ensuring that there are still sufficient safety reserves to protect the occupants in the event of a second, subsequent collision.

The new Audi A6 allroad quattro is also extremely well protected against the consequences of collisions from the rear. The cell is built to withstand an impact against a deformable barrier with 70 percent overlap up to a speed of 80 km/h. In such a collision, the fuel tank also remains outside the actual deformation area courtesy of the rear structure of the car consisting of powerfully proportioned members which absorb all of the impact energy.

More interior space, a wider track: the new Audi A6 allroad quattro is significantly larger than its predecessor. Since the extra width also means a larger frontal area, the aerodynamics engineers were faced with the task of compensating for this fundamental drawback by adopting a particularly elaborate design for the car’s outer skin. Once again, Audi showed itself to be fully up to this task, as testified by the drag coefficient (Cd) of just 0.33 for the new Audi A6 allroad quattro 3.2 FSI. The product of drag coefficient and frontal area is slightly improved in the new model.

One feature that is particularly important in terms of aerodynamics is the underbody panelling. At the front end, the underride protector together with the encapsulation of the engine compartment and transmission ensures a swirl-free flow of air to the central floor area, while wheel spoilers reduce flow losses around the front wheels.

Large cover panels conduct the flow of air along the transmission tunnel all the way back to the rear wheels where it is channelled by the rear underride protector and directed behind the vehicle.

Minimising the uplift at the rear axle is of decisive importance for vehicle handling and stability. The aerodynamic engineers at Audi have developed a separation edge at the top of the tailgate which blends elegantly into the overall design of the rear end. This separation edge significantly reduces the uplift occurring at the rear at motorway speeds.

When travelling at higher speeds, it is the airstream which dominates the overall spectrum of driving noises – just below the recommended autobahn speed of 130 km/h, the air is already flowing around the car at hurricane-like speeds. In the new A6 allroad quattro the acoustic experts at Audi have succeeded in effectively muting the frequency range between 1,000 and 8,000 hertz, as noise in this range is particularly irritating to the human ear.

A triple seal system has been incorporated into the doors to soundproof all of the apertures where sound could enter. When the windscreen wipers are not operating they drop down into a recessed rest position to avoid creating any extra wind noise.

Even when they are in action, the windscreen wipers make surprisingly little noise – this is the result of the new flat wiper technology with its ingenious air routing and of the blades with their integral spoilers.

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