|The new A6 hybrid. Click to enlarge.|
Audi’s redesigned executive-class A6 will offer a choice of four- and six-cylinder powerplants at launch in early 2011: two gasoline engines and three TDI units. Audi has also confirmed production of a hybrid version of the A6—its second hybrid model after the Q5 hybrid quattro—“at a later point”.
The engines have outputs ranging from 130 kW (177 hp) to 220 kW (300 hp). They obtain their fuel through direct injection; the 3.0 TFSI employs a supercharger to achieve boost, and the 2.0 TFSI and TDI operate with turbochargers. Throughout the entire model line, fuel consumption in the A6 has decreased by up to 19% compared to the previous model.
Each of these engines makes use of technologies from the Audi modular efficiency platform. Much effort has gone into optimizing these engines, particularly with regard to internal friction, in keeping with the brand’s thermal management system. Each of the units operates with an energy recovery system combined with a start-stop system, irrespective of the type of transmission used.
The naturally aspirated 2.8 FSI is also equipped with AVS; in this case, it acts on the intake valves. The throttle can usually remain open, allowing the V6 to breathe freely. It has an output of 150 kW (204 hp) and achieves 280 N·m (207 lb-ft) of torque in the speed range of 5,250 to 6,500 rpm. Key data (with multitronic): 0-100 km/h (0-62 mph) in 7.7 seconds; top speed 240 km/h (149 mph); consumption in the EU cycle 7.4 liters per 100 km (32 mpg US), 172 g CO2 per km (277 g/mile). This represents an improvement of 12%, despite the fact that the predecessor delivered 10 kW (14 hp) less.
The most powerful gasoline engine in the A6 family is the 3.0 TFSI; its mechanical charger is situated in the 90-degree V formed by the cylinder banks. The V6 delivers 220 kW (300 hp) of power and 440 N·m (325 lb-ft) of torque, the latter at 2,900 to 4,500 rpm. The A6 3.0 TFSI sprints from standing to backroad speed in 5.5 seconds and reaches an electronically governed top speed of 250 km/h (155 mph). It consumes on average 8.2 liters per 100 km (27 mpg US) and emits 190 g CO2 per km (306 g/mile)—an advance of 13% over the previous model, which produced 213 kW (290 hp).
The most efficient engine in the new A6 is the redeveloped 2.0 TDI. This four-cylinder unit develops 130 kW (177 hp). Its 380 N·m (280 lb-ft) of torque stand at the ready between 1,750 and 2,500 rpm. In conjunction with a manual transmission, it propels the Audi A6 from zero to 100 km/h (62 mph) in 8.7 seconds, then on to a top speed of 228 km/h (142 mph). In the EU cycle, it requires 4.9 liters per 100 km (48 mpg US) and emits 129 g CO2 per km (208 g/mile). That is a 13% decrease in fuel consumption.
The newly developed 3.0 TDI is represented with two versions in the A6 family. Both feature low weight, minimal internal friction, ultra high-precision tuning of the auxiliary units, and a thermal management system that provides separate coolant circuits for the crankcase and cylinder heads.
In the first version, the V6 diesel generates 150 kW (204 hp) and applies 400 N·m (295 lb-ft) of torque in the low range of 1,250 to 3,500 rpm. Paired with a multitronic transmission, it accelerates the A6 to 100 km/h in 7.2 seconds and achieves a top speed of 240 km/h (149 mph). Its average consumption is 5.2 liters per 100 km (45 mpg US), a CO2 emissions level of 137 g per km (220 g/mile). Compared with the 140 kW (190 hp) predecessor, this represents an advance of 19%.
The top-of-the-line version of the 3.0 TDI delivers 180 kW (245 hp), providing 500 N·m (369 lb-ft) of torque between 1,400 and 3,250 revolutions. The standard sprint takes just 6.1 seconds, and top speed is limited to 250 km/h (155 mph). On average, the engine uses 6.0 liters of fuel per 100 km (39 mpg US) and emits 158 g CO2 per km (254 g/mile). As such it outperforms the previous engine, which achieved 176 kW (240 hp), by 16%.
As was the case with the previous model, the new Audi A6 is also available with a wide range of drivetrains. The choice, based on the engine version, will include a manual six-speed transmission, the continuously variable multitronic, and the brand-new, sporty S tronic. Each unit is precisely tuned and features a wide gear-ratio spread, thereby making a significant contribution to the sedan’s efficiency.
Depending on the engine version, power is funneled via the gears to the front wheels or to the quattro permanent all-wheel drive, whose crown-gear center differential and torque-vectoring function achieve the ultimate traction, stability and dynamic response. For the top-of-the-line engines, Audi will offer an optional sport differential.
The Audi drive select dynamic handling system for all TFSI and TDI versions has been expanded to include an additional mode – the “efficiency” program.
Much of the body of the new Audi A6 consists of aluminum and high-tech steels, rendering it light, stiff and safe.
Audi A6 hybrid. The A6 hybrid employs a parallel hybrid concept: Its combustion engine, a 155 kW (211 hp) 2.0 TFSI, works together with an electric motor that delivers 33 kW (45 hp) and 211 N·m (156 lb-ft) of torque. The electric motor sits directly behind the TFSI, occupying the space of the torque converter upstream of the modified 8-speed tiptronic. The transmission sends torque to the front wheels.
A crash-protected area of the luggage compartment houses a light, compact lithium-ion battery that provides 1.3 kWh of nominal power and generates 39 kW. Depending on requirements, it is air-cooled in two ways—by means of a blower from the interior or by means of an internal refrigerant circuit coupled to the automatic air conditioning system. This technology largely maintains the rechargeable battery within the appropriate temperature range, thereby ensuring that the vehicle operates on electric power a comparatively large percentage of the time.
The Audi A6 hybrid can achieve speeds of up to 100 km/h (62.14 mph) purely on electricity; at a constant speed of 60 km/h (37 mph), it has a range of 3 km (1.9 miles). It can also operate with the combustion engine only or in hybrid mode; in the deceleration phases, it recovers power and activates both the engine and the electric motor together when accelerating quickly. Special indicators on the instrument cluster and on the MMI monitor provide of detailed display of the different driving conditions.
The Audi A6 hybrid provides the power of a V6, combined with the fuel efficiency of a four-cylinder engine. It accelerates in 7.3 seconds from zero to 100 km/h (62 mph), top speed is 238 km/h (148 mph) and the average fuel consumption is 6.2 liters per 100 km (38 mpg US), a CO2 emissions level of 142 grams per km (229 g/mile) (performance and fuel consumption figures are provisional).