September 7, 2003

Audi A3 1.6 FSI / A3 3.2 quattro

Audi is adding a thrifty sprinter to the range of versions of its compact sports model, the A3: inside its engine compartment, the A3 1.6 FSI has a four-cylinder engine with FSI petrol direct injection, developing 85 kW (115 bhp) and 155 Nm of torque. 

It propels the dynamic three-door model up to a top speed of 196 km/h; the speedometer needle hits 100 km/h after 10.9 seconds. But this four-cylinder engine has more than just sports talents to recommend it.

The 1.6 litre FSI engine also demonstrates potential for fuel economy thanks to its petrol direct injection technology. The A3 1.6 FSI consumes just 6.5 litres of Super Plus fuel per 100 kilometres, pushing the figure down to a remarkable 5.3 litres per 100 km in extra-urban conditions.

This is undoubtedly an unbeatably low figure for a petrol engine, considering its performance. The 55-litre fuel tank means that a range of over 850 kilometres is possible without pauses for refuelling.

The FSI engine has another pleasing result of its refined engine technology in store for drivers: since the vehicle is classified in emission category EU4, there is a tax exemption in Germany for new cars registered before 1 January 2005.

This new version, which is going into production in August 2003, extends the Audi A3 range to three 4-cylinder petrol engines - as well as the 1.6, there is a further petrol direct injection model in the guise of the 2.0 FSI. The A3 1.6 FSI with six-speed manual gearbox as standard will cost 20,100 in Germany.

Motor sport expertise

In technical terms, the new engine for the A3 is closely related to the racing engine that powered the Audi R8 racing cars to victory at the Le Mans 24 Hours in 2001 and 2002.

Here again it was a combination of more power from less fuel that demonstrated Audi's technological lead in a very literal sense. With lower fuel consumption than conventional racing engines, the cars were able to put in an extra lap between refuelling stops.

Fuel injection under high pressure

The term "petrol direct injection" makes the most significant distinction between this and conventional petrol engines clear: in contrast to indirect injection, the fuel is injected directly into the combustion chamber.

The injector, located on the admission side in the cylinder head, is served by a high-pressure pump driven by the camshaft and a pressure reservoir shared by all cylinders - the common rail system. The injector controls the injection time to within thousandths of a second at injection pressures of up to 110 bar. By comparison, indirect injection operates at a maximum of four bar.

There is a further special feature on the admission side - the tumble flap. This can be adjusted to two different positions on the 1.6 FSI engine, thus specifically influencing the movement of the incoming air.

This makes two different operating modes possible, the prerequisite for the versatility of the FSI principle: homogeneous and stratified-charge operation. Depending on the engine speed, load status and accelerator pedal position, the engine electronics always select the optimum mode - without the driver even noticing.

Homogeneous-charge operation at full load

A conventional engine with indirect fuel injection establishes an ignitable air-fuel mixture of a ratio of 14.7:1 (lambda = 1) throughout the entire combustion chamber. An FSI engine also operates in this mode, known as "homogeneous operation": namely whenever the engine is required to produce a high power output.

At full load, the fuel is injected synchronously with the air intake phase. This fills the combustion chamber evenly. By virtue of the precision injection process, the extremely fine atomisation and the internal cooling effect when the fuel vaporises directly inside the combustion chamber, the FSI engine can run at a higher compression ratio than an engine with an indirect injection system. This permits greater efficiency.

Stratification: maximum consumption reduction

The crucial feature of the new engine that paves the way for fuel-saving, however, is stratified-charge operation at partial loads.

In this operating mode, fuel is not injected until the compression phase. It is now injected directly into the air in the combustion chamber, in which a tumbling movement is induced by the diagonal position of the tumble flap and the special shape of the piston crown.

This specific tumbling movement makes it possible to establish the required stratification: precisely at the point of ignition, the cloud of fuel and air which fills only part of the combustion chamber reaches the spark plug, permitting efficient combustion in spite of the excess air in the remainder of the combustion chamber.

Audi A3 3.2 quattro

The sporty top-of-the-range version of the latest Audi model can now be ordered: the A3 3.2 quattro with six-cylinder engine and completely new transmission technology. The combination of the high-torque 3.2-litre engine, which produces 184 kW (250 bhp), and the innovative sports transmission DSG is a particularly clear indication of the potential of the new Audi A3 as a driving machine.

The Audi A3 3.2 quattro completes the sprint from 0 to 100 kilometres per hour in 6.4 seconds, whilst its top speed is gently governed at 250 km/h. This model has an overall fuel consumption of just 9.8 litres per 100 km. These are figures that speak for themselves, even compared with vehicles with a six speed manual gearbox.

The compact 3.2-litre V6 engine delivers a broad peak-torque range, with a maximum value of 320 Nm between 2500 and 3000 rpm. In conjunction with the ultra-rapid and precise control technology of the new Direct Shift Gearbox DSG, it responds extraordinarily spontaneously to movements of the accelerator pedal.

The revolutionary Direct Shift Gearbox DSG combines all the advantages of a six speed manual gearbox with the qualities of a modern automatic transmission. The driver thus benefits from enormous agility and driving enjoyment as well as from convenient operation and smooth acceleration with an uninterrupted flow of power.

So how does DSG function When driving, one gear is engaged. When the next gearshift point is approached, the appropriate gear is pre-selected but its clutch kept disengaged.

The gearshift process opens the clutch of the activated gear and closes the other clutch at the same time with a certain overlap. The gear change consequently takes place under load, with the result that a permanent flow of power is maintained.

Thanks to optimum gearshift strategies, the control technology integrated into the transmission produces instantaneous gearshifts that are nevertheless smooth and virtually jolt-free. And by moving the gear lever in the manual gate or operating the standard-fit shift paddles behind the steering wheel like in a racing car, the driver can actively influence the choice of gears and the gearshift point at any time.

On the Audi A3 3.2 quattro, a hydraulic multi-plate clutch varies the distribution of power between the front and rear wheels. By distributing propulsive power permanently to all four wheels to suit the situation in hand, the drive system guarantees maximum traction and, as a result, optimum acceleration.

At the same time there are still ample reserves for transmitting cornering forces in the interest of cornering safety and directional stability. The arrangement of the engine at the front and the multi-plate clutch at the rear is beneficial to axle-load distribution. Indeed, this weight distribution is crucial to the excellent directional stability and good handling of the A3 3.2 quattro.

A 17-inch dual-piston brake system adapted from the version used on the Audi RS 4 assures the appropriate braking performance; the front discs measure a generous 345 millimetres in diameter. The standard sports suspension is fitted with 17-inch cast aluminium wheels and size 225/45 tyres. This combination not only looks extremely dynamic, but also offers excellent running qualities on both dry and wet roads.

The A3 3.2 with DSG and the Ambition equipment line costs 32,850 in Germany. As an alternative, the A3 3.2 quattro is also available with a six-speed manual gearbox for 31,000. Deliveries of both versions will start this year.