Camouflaged versions of new Audi compact hatchback tackle a course also used for the Azores rally to demonstrate latest quattro technology
- quattro-equipped versions of all-new compact hatchback showcase the latest evolution of the world renowned technology
- Quick-witted: progressive steering with a variable ratio
- No need to compromise on agility or comfort: adaptive damper control
Roads considered challenging enough to be a test of mettle for thoroughbred competition cars on the Azores rally have been chosen to provide a baptism of fire for the quattro system underpinning the all-new Audi A3. Journalists have been able to assess the dynamic capabilities of all-wheel-drive versions of the advanced new compact hatchback on these roads, which snake around the island of São Miguel in Portugal’s Azores archipelago, ahead of the car’s world public debut at next month’s Geneva Motor Show.
Pure emotion: the original thought
In a place where volcanoes once created a whole chain of islands and where there is a high level of volcanic activity, Audi is demonstrating the core of its DNA: quattro drive. The all-wheel drive system fittingly makes its first appearance in one of the most emotive versions of the fourth generation A3, and represents the latest stage in the evolution of this successful technology, which in Audi models with transverse engine installations is based around an electro-hydraulic multi‑plate clutch.
Managed by precisely tuned software, the system not only maximises stability, grip, and driving pleasure, but is also extremely efficient. Supported by the adaptive suspension and the progressive steering, it delivers composed, surefooted and incisive driving characteristics that impress over tight winding roads and varied mountain and valley stretches in particular.
Intelligent regulation: the quattro drive in detail
The clutch is located at the end of the prop shaft, in front of the rear axle differential – a position that benefits the axle load distribution in particular. Inside is a package of plates that operate in an oil bath. Its metal friction rings are arranged behind one another in pairs – one ring of each pair is rigidly meshed with the clutch housing, which rotates with the prop shaft; the other ring is meshed with the short output shaft to the rear axle differential.
Audi tailored the electronic torque distribution control specifically to suit the new A3 and integrated it in the Audi drive select dynamic handling system. It takes the data of the suspension sensors into account and detects not only the driving conditions and road properties but also the driving style. The control unit uses this data as a basis to calculate a torque distribution that provides optimum efficiency and passes the value on to the clutch. This is particularly efficient.
The all-wheel drive distributes the torque with full variability between the front and rear axles. During normal driving operation, the majority of the engine’s power is transmitted to the front wheels. When driving off or when the front axle has little traction, the clutch diverts the torque at lightning speed: In this case, an electric axial-piston pump is activated, which applies up to 44 bar of hydraulic pressure to the clutch plates. The more the clutch plates are pressed together by this pump, the more drive torque is transmitted to the rear axle – the maximum is 100 percent. The clutch can already transmit part of the torque to the rear axle when the driver begins to make quicker turns of the steering wheel during more challenging driving. As soon as the driver accelerates, the torque presses the A3 into the corner.
During load changes, the distribution of torque allows precise turning into the bend, which further increases driving dynamics.
Full control: the Electronic Stabilisation Control
The wheel-selective torque control, a software function of the Electronic Stabilization Control (ESC), perfectly complements the latest quattro system. When the new Audi A3 negotiates a corner at high speed, the program applies the brakes slightly to the two wheels on the inside of the bend. The difference in drive forces on both axles turns the car into the bend, allowing it to follow the steering angle precisely. This makes the handling even more agile, fluid, and safe.
The perceived response of the quattro drive is also changed in the three functional modes of the ESC. This allows the traction and driving stability to be adapted to the driver’s request. If the ESC has to regulate, its adjustments are gentle and virtually imperceptible.
Maximum power transmission is ensured in
ESC ON mode. This means that acceleration is safe and stable and performed with as little wheel slip as possible. By selecting
Sport mode, the driver can drift on surfaces with a low coefficient of friction, such as snow, in a controlled, safe manner. The greater wheel slip in this case provides increased driving pleasure. In
ESC OFF mode, the amount of possible wheel slip is virtually unlimited.
Variable in every situation: the progressive steering
Due to their design, conventional steering systems always require a compromise between directness and comfort. The electromechanical progressive steering that will be a feature of more performance-oriented versions of the new Audi A3 solves this conflict. Its toothed rack and pinion have a special shape and toothing. This results in different gear ratios depending on the steering angle. When the steering wheel is turned quickly during faster driving, it is smaller and the steering is very direct. This decreases the steering effort in urban traffic and while manoeuvring and increases the level of comfort considerably.
On twisting roads, the progressive steering facilitates an even more spirited driving style. The steering wheel has to be turned just 2.5 times between locks; the steering ratio in the centre position is 14.3:1. The power assistance is in perfect harmony with this character and adapts to the driving speed. At low speeds, it is higher in order to enable easier manoeuvrability; as the speed increases, the power assistance is decreased continuously. This allows the driver to experience reassuringly weighty steering feel even when driving at high speed on the motorway.
The progressive steering is equipped with a highly efficient electromechanical drive that supplies power only when it is needed. It works together closely with various assist systems, such as the adaptive cruise assist, the collision avoidance assist, and the park assist.
New damper technology in the compact model: the adaptive suspension
Comfortably soft or sporty and taut? Both are possible with the suspension with adaptive damper control which will be available for selected models in the new range. Three damper settings ensure that the driver can experience the spread of the driving characteristics and enjoy particularly agile handling. Sensors measure the vertical acceleration of the body structure and the relative movement of the individual wheels in relation to it. The control unit processes its signal in a matter of milliseconds and continually adapts each damper to the condition of the road, the driving situation and the driver’s requests. The dampers include electromagnetically actuated valves that can be regulated extremely quickly and in a highly energy-efficient way. Depending on their position, they allow the hydraulic fluid to flow faster or slower, which changes the characteristics of the dampers between a soft setting for long distance ride pliancy and a firmer footing for faster A and B-road driving.
The driver can switch the basic damper settings between the three modes comfort, auto and dynamic in the Audi drive select system, which will be a standard feature of the majority of models in the new A3 range. Overall, Audi drive select offers a total of five modes – comfort, auto, dynamic, efficiency, and individual – accessed via a physical button located near the gearshift or selector lever. If the driver selects the “individual” setting, they can freely specify their personal preferences to a great extent.
As well as the damper control, Audi drive select can also influence the operating characteristics of the throttle, steering and, where fitted, the S tronic transmission and quattro drive. Its setting also impacts on comfort and safety systems including the automatic air conditioning, matrix LED headlights, seat belt tensioners and adaptive cruise control, where these are fitted.
