New high-tech engine: the 2.0 TFSI
From a displacement of 1,984 cm3 the 2.0 TFSI generates 140 kW (190 hp); it provides 320 Nm (236.0 lb-ft) of torque between 1,500 and 4,200 rpm. The all-new engine design combines sporty power and exemplary efficiency: In just 6.7 seconds the new A3 with the seven-speed S tronic sprints from 0 to 100 km/h (62.1 mph), reaching a top speed of 244 km/h (151.6 mph). The manual transmission model attains an NEDC consumption rate of just 5.5 liters per 100 kilometers (42.8 US mpg), which equates to CO2 emissions of 126 grams per km (202.8 g/mi).
The high-tech four-cylinder engine embodies a new strategy: the continued development by Audi of successful engine downsizing into rightsizing. In a moderate gear, customers of the new Audi A3 experience the consumption benefits of a smaller unit; for a sporty driving style they need not accept its disadvantages. The relatively large displacement is no handicap, but rather a prerequisite for an innovative combustion process.
The new combustion process takes advantage of a longer expansion of the combustion gas in order to convert thermal energy more effectively. This is possible in the 2.0 TFSI thanks to the real shortening of the compression phase in conjunction with a higher compression ratio of now 11.7:1.
The intake valves close much earlier than usual – in interplay with an increased pressure in the intake manifold they reduce throttle losses during intake in the partial load range. Owing to the shortened compression, for compressing a particular certain mass of fresh gas to the compression pressure of a comparable 1.4-liter engine, the 2.0 TFSI requires about the same effort as the 1.4 TFSI. In the subsequent expansion phase, the engine delivers work and fully exploits the two liters of displacement. The approximately 40 percent longer expansion of the combustion gas compared with the 1.4 TFSI leads to more engine work delivered at the same rate of fuel consumption. This leads to a significant increase in efficiency in wide areas of the characteristic map.
So that the charge sufficiently swirls despite the short inlet time, the combustion chambers, piston recesses and inlet ducts as well as the turbocharging of the new 2.0 TFSI are specially tuned to the new combustion method. At higher loads, the Audi valvelift system closes the intake valves later and thereby allows higher filling for good power and torque delivery. The injection pressure is increased to 250 bar.
The technical finesses of the new 2.0 TFSI also include the exhaust manifold integrated in the cylinder head, the rotary slide module for thermal management, the Audi valvelift system (AVS) for the intake valves and the electrical wastegate of the turbocharger and dual injection – in the partial load range indirect intake manifold injection direct injection.