The engines used in the A4 model series – four TFSI gasoline and six TDI units – combine sportiness and efficiency in a groundbreaking manner. All engines follow Audi’s downsizing principle. They feature forced induction and direct injection for tremendous pulling power. Even the entry-level four-cylinder engine produces 230 Nm (169.64 lb-ft) of torque. The start-stop system is standard for all models. CO2 emissions have decreased by 11 percent on average across the board, with the individual reductions as high as 19 percent. At the same time, performance has increased with many of the engines.
Thoroughly redesigned: the 1.8 TFSI
Even the lowest-displacement engine in the lineup, the 1.8 TFSI, demonstrates Audi’s engine expertise to the full. Audi development engineers have thoroughly enhanced the four-cylinder unit and created new solutions regarding numerous aspects of engineering. The results are powerful performance and astonishingly low fuel consumption. The high-end four-cylinder unit has a torque curve similar to that of a TDI. Maximum torque of 320 Nm (236.02 lb-ft) is available at just 1,400 rpm and remains constant up to 3,700 rpm. Maximum output of 125 kW (170 hp) is achieved at just 3,800 rpm.
The 1.8 TFSI accelerates the Audi A4 Sedan from zero to 100 km/h (62.14 mph) in 8.1 seconds on its way to a top speed of 230 km/h (142.92 mph). Yet it requires just 5.7 liters of fuel per 100 km (41.27 US mpg) on average – a CO2 equivalent of 134 grams per km (215.65 g/mile). Consumption has been reduced by a full 18 percent compared with the previous-model engine that produced 118 kW (160 hp).
A major innovation in the 1.8 TFSI is the addition of indirect fuel injection. Complementing FSI direct fuel injection, it is active at part load, where it reduces fuel consumption and particulate emissions. FSI direct fuel injection comes into play when starting and at higher loads. The Audi engineers achieved new degrees of freedom when it comes to charging efficiency in the combustion chambers. Both camshafts can be adjusted as needed, plus the Audi valvelift system adjusts the lift of the valves on the exhaust side to minimize gas exchange losses.
The innovative thermal management system features a further innovation: Two rotating cores control the flow of coolant. These valves ensure that the engine oil heats up to its operating temperature soon after the vehicle is started; they also maintain the coolant temperature, as per a given driving situation, between 85 and 107 degrees Celsius (185.0° F and 224.6° F). As a result – regardless of load or engine speed – the valves always strike the perfect balance between minimal friction and high thermodynamic efficiency.
The exhaust manifold of the compact four-cylinder unit is integrated into the cylinder head, where it is bathed in water. This solution reduces the exhaust gas temperature. The turbocharger is also a new development. Its most important innovation is an electric wastegate actuator that adjusts the boost pressure particularly quickly and precisely, optimizing engine response.
Despite all the new technologies and the added performance, Audi has reduced the weight of the 1.8 TFSI from 135 to 131.5 kilograms (297.62 lb to 289.91 lb). Internal friction has also been significantly reduced by the use of an innovative coating on the piston skirts and by mounting the two balance shafts that provide for smooth operation in roller bearings.
The regulated oil pump requires little energy itself, and a high-precision electric system controls the piston heads with jets of oil.
The TFSI: from 88 kW (120 hp) to 200 kW (272 hp)
The entry-level gasoline engine is the 1.8 TFSI with 88 kW (120 hp) and 230 Nm (169.64 lb-ft) of torque. It accelerates the Sedan to 100 km/h (62.14 mph) in just 10.5 seconds and reaches a top speed of 208 km/h (129.25 mph), yet consumes just 6.5 liters of fuel per 100 km (36.19 US mpg) on average.
The 2.0 TFSI, a born winner that was named Engine of the Year five times in a row from 2005 through 2009, is the mid-range gasoline engine in the A4 portfolio. Its highlights include adjustable intake camshafts, the Audi valvelift system at the exhaust end, two balance shafts, minimized internal friction, the turbocharger and the regulated oil pump.
The 2.0 TFSI – the only spark-ignition engine also available in the A4 allroad quattro – delivers 155 kW (211 hp) and 350 Nm (258.15 lb-ft) of torque, the latter between 1,500 and 4,200 rpm. Paired with the six-speed manual transmission and quattro drive, it accelerates the A4 Sedan to 100 km/h in 6.5 seconds on the way to a top speed of 246 km/h (152.86 mph). Its average fuel consumption is 6.8 liters per 100 km (34.59 US mpg), which corresponds to 159 grams of CO2/km (255.89 g/mile).
Somewhat later, Audi will introduce the most powerful gasoline engine: the supercharged 3.0 TFSI. The supercharger located in the 90-degree V of the cylinder banks is belt-driven by the crankshaft. Two opposed pistons inside the supercharger rotate at over 20,000 rpm, with the air gap between them measuring just a few thousandths of a millimeter. The compressor first compresses the intake air to as high as 0.8 bar before it is subsequently cooled down again by two intercoolers.
The compressor is behind the throttle valve, which boosts the former’s efficiency. The gas travel paths behind the compressor are short so that torque is generated early and quickly. An extensive array of measures makes the supercharger less noisy.
A balance shaft in the engine’s light-alloy crankcase enhances smooth running. Adjustable intake camshafts and tumble flaps in the intake ports provide for good charging efficiency in the combustion chambers.
Its willingness to rev, its pulling power and its cultivated, sonorous sound make the 3.0 TFSI a sporty and dramatic engine. It generates 200 kW (272 hp) and a brawny 400 Nm (295.02 lb-ft) of torque between 2,250 and 4,750 rpm. The A4 Sedan completes the standard sprint in just 5.9 seconds, and top speed is limited to 250 km/h (155.34 mph). Standard fuel consumption is just 8.1 l/100 km (29.04 US mpg), corresponding to CO2 emissions of 190 grams per kilometer (305.78 g/mile). A second version of the 3.0 TFSI, with 245 kW (333 hp), powers the S models.
Powerful and highly efficient: The TDI engines
TDI engines from Audi stand not only for high efficiency, but also for a smart, modern type of sportiness. Their powerful performance, immense torque, low fuel consumption and cultivated operation combine for a harmonious overall impression.
Even the 2.0 TDI is a powerful engine. Audi offers five versions of it for the Sedan and the Avant. The first version delivers 88 kW (120 hp) and 290 Nm (213.89 lb-ft) of torque, the latter between 1,750 and 2,500 rpm. The second variant puts out 100 kW (136 hp) and 320 Nm (236.02 lb-ft); the third 105 kW (143 hp). With the fourth version, which has undergone a series of detailed optimizations, these figures are 120 kW (163 hp) and 380 Nm (280.27 lb-ft). The 130 kW (177 hp) version is optionally available with quattro drive. The 2.0 TDI with 105 kW (143 hp) and 130 kW (177 hp) are also available for the A4 allroad quattro.
The technical specialties of both four-cylinder diesel engines are the low internal friction, a turbocharger with adjustable vanes, and a new centrifugal governor in a dual-mass flywheel (in versions with 100, 120 or 130 kW [136, 163 and 177 hp]).
Thanks to its sophisticated design, the flywheel only requires a slight mass to compensate for most of the vibrations caused by the engine. This makes the engine even smoother at low revs, which permits earlier upshifts and thus more efficient driving. Fuel consumption decreases by as much as 0.2 liters per 100 km.
The most efficient variant in the model family is the A4 2.0 TDI with 100 kW (136 hp). The Sedan requires just 4.3 liters of fuel per 100 km (54.7 US mpg) on average – a CO2 equivalent of 112 grams per km (180.25 g/mile). It boasts impressive performance, accelerating from zero to 100 km/h in 9.3 seconds on its way to 215 km/h (133.59 mph). In the Sedan the A4 2.0 TDI with 120 kW (163 hp) manages with 4.4 liters of diesel per 100 km (53.46 US mpg) on average. This equates to 115 grams CO2 per km (185.07 g/mile). Its other key data: zero to 100 km/h (62.14 mph) in 8.4 seconds, top speed 225 km/h (139.81 mph).
When installed in the Sedan, the four-cylinder diesel with 88 kW (120 hp) averages 4.5 liters per 100 km (52.27 US mpg). The standard sprint takes 10.5 seconds, and top speed is 205 km/h (127.38 mph). The A4 2.0 TDI with 105 kW (143 hp) also consumes 4.5 liters of diesel per 100 km (52.27 US mpg) on average in the Sedan. The sprint to 100 km/h (62.14 mph) takes 9.2 seconds, and top speed is 216 km/h (134.22 mph). Equipped with the 2.0 TDI producing 130 kW (177 hp), the Sedan posts a top speed of 230 km/h (142.92 mph) and a zero-to-hundred (62.14 mph) time of 8.2 seconds. Its average fuel consumption: 4.6 liters per 100 km (51.13 US mpg).
Powerful and cultivated: the V6 TDI units
At the top of the TDI range are two cultivated V6 diesel units with a displacement of 3.0 liters. Their most important features are the weight of just over 190 kilograms (419 lb), the energy-saving chain drive, low internal friction, the regulated oil pump and particularly sophisticated thermal management. The crankcase and the cylinder heads have separate coolant circuits connected to one another via valves.
The 3.0 TDI with 150 kW (204 hp) is the most efficient V6 diesel we have ever built. Audi specifically designed it for maximum fuel efficiency: from the camshafts’ control times through the turbocharger to the common-rail system providing injection pressure up to 2,000 bar.
The 3.0 TDI produces 400 Nm (295.02 lb-ft) of torque between 1,250 and 3,500 rpm. It propels the Sedan with multitronic from 0 to 100 km/h (62.14 mph) in 7.1 seconds en route to a top speed of 235 km/h (146.02 mph). It averages just 4.9 liters of fuel per 100 km (48.0 US mpg), with CO2 emissions of 129 g/km (207.61 g/mile).
The most powerful version of the 3.0 TDI – which is also available for the A4 allroad quattro and will be offered as a clean diesel version somewhat later – generates 180 kW (245 hp) and 500 Nm (368.78 lb-ft) of torque, with the latter available between 1,400 and 3,250 rpm. With this engine, the sedan completes the standard sprint in 5.9 seconds and reaches an electronically limited top speed of 250 km/h (155.34 mph). Average fuel consumption is just 5.7 liters of fuel per 100 km (41.27 US mpg), which corresponds to 149 grams of CO2/km (239.79 g/mile).
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.