More power, lower fuel consumption – the new Audi A4 is being launched in North America with a choice of two powerful yet refined engines. All powerplants have direct fuel injection – the engines use FSI technology while the four-cylinder gasoline engines are turbocharged – with a correspondingly impressive torque.
With their splendid flow of power, the powerplants in the new A4 deliver pure driving pleasure. At the same time, compared to the corresponding predecessors, their fuel consumption dropped by more than 10 percent – for Audi, power and efficiency always belong together.
FSI: The supreme gasoline technology
The new A4 is being launched with two gasoline engines. The 3.2 FSI is a V6 with 265 hp. The newly developed four-cylinder 2.0 TFSI is available with 211 hp. With these engines, Audi is once again extending its lead in engine design – using the gasoline direct injection technology known as FSI, which is superior to anything offered by the competition. With this technology, fuel is injected under high pressure into the combustion chambers and at the same time intensely swirled. The evaporation achieved in this way withdraws heat from the combustion chambers, thus allowing for a high compression ratio that contributes significantly to a highly efficient combustion process. FSI engines develop more power and are more dynamic than conventional engines with fuel injection into the intake pipes, yet they also make more economical use of fuel.
Gasoline direct injection from Audi first demonstrated its potential for superior performance in June 2001, when an engine featuring gasoline direct injection took the Audi R8 sports prototype to overall victory in the Le Mans 24 Hours. In the years that followed, the car entered 80 races and won 64 of them – evidence not only of the power of the engines but also of the uncompromising commitment to reliability and quality that is typical of the Audi attitude to both motorsport and
production.
In keeping with its efficiency strategy, Audi has improved its FSI technology further. In the V6 and the new two-liter four-cylinder engine, it is combined with the innovative valve control technology known as Audi valvelift system. The turbocharger on the four-cylinder combines the free-revving nature with high torque – an exemplary blend.
The old turbo engine problem – the high combustion chamber temperatures and the resulting knocking tendency – is resolved by using direct injection. This allows Audi to achieve a higher compression ratio in its TFSI engines, which in turn leads to improved thermodynamic efficiency.
Top gasoline engine: The 3.2 FSI
The reassuring hum of the magnificent 3.2 FSI introduces the top-of-the-line gasoline engine in the new Audi A4; it has been enhanced extensively. It is a member of the modern Audi family of V engines, and is characterized, like all Audi V6 units, by a 90-degree cylinder angle, compact dimensions and a low weight, with a crankcase made from an aluminum-silicon alloy. This contributes to the low overall weight of the new Audi A4 and its excellent axle-load distribution.
From a displacement of 3,197 cc, the 3.2 FSI develops 265 hp and delivers its maximum torque of 243.40 lb-ft all the way from 3,000 to 5,000 rpm. Compared with the previous model, which had a power output of 255 hp, fuel consumption has been reduced. The 3.2 FSI is available with six-speed Tiptronic; quattro permanent all-wheel drive is standard as well in North America.
About half of the improvement in fuel consumption in the 3.2 FSI is due to the Audi valvelift system (AVS). This new technology, which controls valve lift in two stages, ensures excellent combustion chamber filling in all situations. It regulates the amount of combustion air drawn into the engine by varying inlet valve lift; in most cases the throttle butterfly can therefore remain fully open, which largely eliminates undesirable throttling losses. The engine breathes freely, develops more power and torque, but consumes less fuel. Depending on load and engine speed, an intake-pipe valve switches between long aspiration pathways for excellent acceleration and short ones for peak power.
A further advance in the 3.2 FSI are the timing chains for the camshafts; typical for the Audi V engines, they operate in the back of the engines and take up less space. The idler wheels and the shaft drive gears have a larger number of teeth, resulting in quieter operation and reduced forces exerted on the chains. A similar effect is achieved by the tri-oval, i.e., slightly triangular shape of the gear wheels. The oil pump delivery volume has been reduced by 30 percent, and it now operates by varying the volumetric flow according to actual demand. The net result is that frictional engine losses have been reduced greatly.
The new 2.0 TFSI
The base engine in the new Audi A4 is the 2.0 TFSI. The turbocharged fourcylinder unit is the successor of the highly successful two-liter engine, which, since 2005, has been voted ‘Engine of the Year’ three times in succession by an international jury of journalists.
The new 2.0 TFSI’s most significant characteristics are an inlet camshaft that adjusts variably through up to 60 degrees of crankshaft rotation and two balancer shafts rotating with double the speed of the crankshaft in the crankcase. They compensate the free second-order inertial forces and lead to refined running with very low vibrations.
The injection in the 2.0 TFSI itself demonstrates the innovative status of Audi technology. The newly developed six-hole injectors deliver the fuel into the combustion chambers with a pressure of 150 bar (2175.1 psi). The result is efficient combustion, enhanced by valves for vortexing the injection. A watercooled turbocharger increases the filling of the cylinders with air; optimized turbine and compressor wheels have improved its reaction. The intercooler is a new development as well, combining a high degree of efficiency with low weight and small dimensions.
The two-liter TFSI engine has the new Audi valvelift system. Unlike the 3.2 FSI, here it facilitates variable control of the exhaust valves, which means that the charge cycle can be drastically improved. The 2.0 TFSI in the Audi A4 thus reaches its maximum torque of 258 lb-ft at an engine speed of just 1,500 rpm. This technology continues to ensure an extremely quick and dynamic build-up of torque, guaranteeing excellent agility and spontaneity.
The new Audi technology plays just as important a role in achieving high efficiency as does the consistent improvement of all components to minimize friction – with important advances made in the area of cylinders and connecting rod bearing linings. The oil pump operates with volume-regulated delivery and two-stage pressure control, which reduces fuel consumption.
The 2.0 TFSI delivers a sporty performance of 211 hp and a mighty 258 lb-ft of torque, available from 1,500 to 4,200 rpm. This powerplant will be available in North America with quattro drive and both manual and Tiptronic transmissions for sedan (Tiptronic only in Avant). Alternately, Audi delivers the A4 sedan 2.0 TFSI with front-wheel drive with the continuously variable multitronic. In its fuel consumption, the new TFSI is amazingly frugal: The high torque allowed the developers to somewhat extend the transmission ratio – an important factor in the efficiency concept.
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