Audi will initially offer the A1 with four engines. The two TFSI gasoline engines and both TDI diesels cover a power range from 63 kW (86 hp) to 90 kW (122 hp). All of the engines combine direct injection and turbocharging technologies. This innovative concept in conjunction with start-stop and recuperation systems delivers ample power with minimal fuel consumption. Figures range between 3.8 and 5.3 liters/100 km (44.38 and 61.90 US mpg).
Downsizing perfected: the gasoline engines
The abbreviation TFSI represents the combination of direct injection and turbocharging, a technology that Audi was the first carmaker in the world to introduce five years ago. The two technologies make an ideal couple. The fuel injected directly into the combustion chambers is extremely turbulent, thus cooling the chamber walls. This reduces the temperature, thus reducing an age-old problem inherent to all turbocharged engines – a tendency to knock due to the high amount of heat produced during combustion. Audi can also operate its TFSI engines with a high compression ratio, which plays a major role in their efficiency.
The smaller of the two gasoline engines is the 1.2 TFSI. It generates 63 kW (86 hp) and delivers its peak torque of 160 Nm (118.01 lb-ft) between 1,500 and 3,500 rpm. Coupled with a five-speed manual transmission, the four-cylinder unit accelerates the A1 from 0 to 100 km/h (0 – 62.14 mph) in 11.7 seconds on its way to a top speed of 180 km/h (111.85 mph). In the EU cycle, it consumes only 5.1 liters of fuel per 100 km (46.12 US mpg), which corresponds to only 118 grams of CO2/km (189.90 g/mile).
The newly developed 1.2-liter engine embodies Audi’s downsizing philosophy: substituting engine displacement with forced induction. Having two valves per cylinder and displacing just 1,197 cc, it is rigorously designed for low weight. The piston rings with their low pre-tension and the compact main and connecting rod bearings of the crank shaft are optimized for low friction, and the demand-regulated oil pump requires little energy itself.
The cast aluminum crankcase of the 1.2 TFSI has its own cooling loop separate from the cylinder head. A regulated water pump ensures that the water in the block is not circulated immediately after the engine is started, enabling the engine to come up to temperature more quickly and shortening the phase of greater frictional resistance due to cold oil.
The high-pressure injection valves spray the fuel into combustion chambers at up to 150 bars of pressure. The turbocharger has an electric actuator that actuates the wastegate flap particularly quickly and precisely. Boost pressure develops spontaneously and fuel consumption under partial load decreases. The intercooler is located in the intake manifold, which benefits spontaneous response.
The 1.4 TFSI ups the ante with 90 kW (122 hp). Its peak torque of 200 Nm is available continuously from 1,500 to 4,000 rpm – the more powerful gasoline engine in the A1 lineup can also be operated at low speeds in almost any situation. The 1,390 cc engine with four valves per cylinder is pressurized by a turbocharger with a water-cooled intercooler.
Paired with the seven-speed S tronic, the 1.4 TFSI gets the A1 up to 100 km/h (62.14 mph) in 8.9 seconds. Top speed is 203 km/h (126.14 mph). With the manual six-speed transmission to follow a short time later, the figures are also 8.9 seconds and 203 km/h (126.14 mph). Average fuel consumption is just 5.2 l/100 km (45.23 US mpg) for the S tronic and 5.3 l/100 km (44.38 US mpg) for the manual transmission. CO2 emissions for the A1 1.4 TFSI with the S tronic are 119 g/km (191.51 g/mile). [these are provisional values for A1 1.4 TFSI with six-speed transmission]
Groundbreaking efficiency: the TDI engines
The 1.6 TDI, which displaces 1,598 cc, is characterized by the systematic minimization of internal friction. The most important measures involve the regulated oil pump, the piston rings, the honing of the cylinder barrels, the toothed belt and the bolts of the cast-aluminum pistons.
Their DLC coating is a novel technology with its roots in racing engine construction. DLC stands for diamond-like carbon – a fine, diamond-like carbon coating.
The piezo injectors of the common rail system can perform six separate injection operations per work cycle, which benefits the quality of combustion, exhaust formation and cultivation. A tangential channel in the intake manifold imparts a targeted swirl to the inflowing air, and the spiral channel fills the combustion chambers. A turbocharger with adjustable turbine geometry and an unthrottled intake and charge air system round out the overall concept.
Audi offers two versions of the 1.6 TDI. The more powerful version produces 77 kW (105 hp) and 250 Nm (184.39 lb-ft) of torque, which is available between 1,500 and 2,500 rpm. It is mated to a five-speed manual transmission. The compact TDI with four valves per cylinder accelerates the A1 powerfully through the standard sprint in 10.5 seconds before reaching a top speed of 190 km/h (118.06 mph) while consuming an average of just 3.9 liters/100 km (60.31 US mpg).
The second version of the 1.6 TDI (cited figures are provisional) to follow somewhat later generates 66 kW (90 hp) and 230 Nm (169.64 lb-ft) of torque, the latter of which is available between 1,500 and 2,500 rpm. In combination with the five-speed manual transmission, the diesel accelerates the A1 from 0 to 100 km/h (0 – 62.14 mph) in 11.5 seconds. It reaches a top speed of 182 km/h (113.09 mph) and offers groundbreaking fuel economy of 3.8 liters/100 km (61.90 US mpg), an equivalent of 99 grams CO2/km (159.33 g/mile).
All four engines in the A1 use a technology from the Audi modular efficiency platform: the recuperation system uses intelligent voltage control for the generator to recover energy during the braking and coasting phase. The energy is stored temporarily in the battery and flows back into the on-board electrical system, relieving the load on the generator and thus the engine the next time the car accelerates.
The start-stop system, another technology from the modular efficiency platform, is also standard with all four engines. This turns the engine off when the car is at rest, if the gear selector lever is in neutral and the driver’s foot has left the clutch pedal. Start-stop then turns the engine back on as soon as the clutch pedal is depressed – all the while functioning quietly, conveniently, and quickly. The start-stop system, which the driver can deactivate at any time, also harmonizes perfectly with the seven-speed S tronic in the 1.4 TFSI.
High-end transmission: the seven-speed S tronic
The seven-speed S tronic combines the convenience of a torque converter transmission with the dynamics and efficiency of a manual transmission. It comprises two subunits and integrates two multi-plate clutches that control the various gears. The large K1 clutch located on the outside directs the torque via a solid shaft to the gear wheels for the odd-numbered gears 1, 3, 5 and 7. A hollow shaft rotates around the solid shaft. It is connected to the smaller K2 clutch, which is integrated into the inside of its larger sibling, and which controls the gear wheels for the even-numbered gears 2, 4 and 6, as well as reverse gear.
Both transmission structures are continuously active, but only one is connected to the engine at any one time. For example, when the driver accelerates in third gear, the fourth gear is already engaged in the second transmission structure. Shifts are performed by switching the clutches. Shifting gears takes only a few hundredths of a second and is completed with no perceptible interruption of traction. Shifts are so fluid, dynamic and smooth as to be barely noticeable.
Only 37 centimeters (14.57 in) long, the seven-speed S tronic is very compact and weighs only around 70 kilograms (154.32 lb), which is extremely light for a high-end transmission. Its two clutches run dry, without a separate oil supply, further adding to the already impressive efficiency. Oil is required to operate the transmission; the oil pump responsible for supplying the oil is demand-regulated. The seven gears are laid out for a sporty response, with the top gear being high-geared to reduce engine speed. This, too, reduces fuel consumption.
The driver can operate the seven-speed S tronic via a selector lever or optional paddles on the steering wheel, as in a sports car. There are also two fully automatic operating modes available. In D mode, the transmission management system operates the engine as often as possible at low speeds; in S mode, the driving style is sporty and the engine speeds higher. A hill-start assist, which holds the A1 in place when starting on a hill, is standard with the S tronic. It can be ordered separately for the A1 with a manual transmission.
The equipment and data specified in this document refer to the model range offered in Germany. Subject to change without notice; errors and omissions excepted.