Second-generation Audi A7 Sportback features standard 48V MHEV system with gasoline or diesel engines
Audi has unveiled the second-generation A7 Sportback, which is the essence of Audi‘s new design language. The four-door coupé brings the show car design of the prologue studies (earlier post) to production.
The drive system features a new mild-hybrid system (MHEV) as standard. At market introduction the coupé will be available with either a 3.0 TFSI (gasoline) or a 3.0 TDI (diesel) engine. With either engine, the MHEV system is based on a newly developed 48-volt primary electrical system and a belt alternator starter (BAS) generating up to 12 kilowatts of recuperation power.
The A7 Sportback can coast with the engine off over a wide speed range and then restart smoothly via the BAS. The start-stop function now activates at 22 km/h (13.7 mph). The 3.0 TFSI is mated to a seven-speed S tronic; the 3.0 TDI to an eight-speed tiptronic. In combination with the S tronic, the quattro drivetrain uses the efficient ultra technology that activates rear-wheel drive as needed.
The 3.0 TFSI, a turbocharged V6, has an output of 250 kW (340 hp) and 500 N·m (368.8 lb-ft) of torque. It accelerates the four-door coupé from 0 to 100 km/h (62.1 mph) in 5.3 seconds on its way to a top speed of 250 km/h (155.3 mph). In the NEDC, the base version of the Audi A7 Sportback 55 TFSI consumes 6.8 liters of fuel per 100 kilometers (34.6 mpg US), corresponding to 154 grams CO2 per kilometer (247.8 g/mi).
The new three-liter V6 exhaust end lies inside the 90° vee; the short gas paths and the twin scroll charger, which prevents unwanted interactions between the gas columns, guarantee spontaneous throttle response. The B-cycle combustion process (a modified Miller cycle, earlier post), which is designed specifically for part load, makes the V6 gasoline engine particularly efficient.
To support it, the Audi valvelift system (AVS) adjusts the intake valve opening times and stroke in two stages based on load and engine speed. The three-liter gasoline unit produces a subtle and sonorous sound that never becomes intrusive even under load. This is due in part to the new tube guide in the dual-branch exhaust system that largely eliminates hum frequencies.
The V6 TFSI has shed 14 kilograms (30.9 lb) and now weighs 172 kilograms (379.2 lb). Its aluminum crankcase features integrated, thin-walled cylinder liners of gray cast iron. In combination with the newly developed rings for the aluminum pistons, this reduces friction.
Another efficiency element is thermal management with separate cooling loops for the crankcase and cylinder head. The exhaust manifold is integrated in the cylinder head and bathed in coolant. This helps the engine to heat up quickly following a cold start. When the engine is warm, this solution lowers the exhaust temperature, reducing fuel consumption, particularly during sporty driving.
For power transmission, the Audi A7 Sportback 55 TFSI is equipped with a seven-speed S tronic, which has been redesigned in many details in view of the high torque. The double-clutch transmission changes gears quickly and almost imperceptibly; with its electrically driven oil pumps and pressure accumulator, it can do so during coasting with the engine stopped.
The 3.0 TDI produces 210 (286 hp) and 620 N·m (457.3 lb-ft) of torque, and accelerates from 0 to 100 km (62.1 mph) in 5.7 seconds. It consumes in the base version just 5.5 liters of fuel per 100 kilometers (42.8 mpg US) in the NEDC, corresponding to 142 grams CO2 per kilometer (228.5 g/mi). Additional four and six-cylinder engines will follow after the market introduction in early March 2018.
Weighing just 190 kilograms (418.9 lb), the 3.0 TDI combines numerous high-tech features. These include particularly complex thermal management, newly developed cylinder heads, greatly reduced friction, a modified chain drive and an electrically adjustable turbocharger that develops up to 2.0 bar of boost pressure.
The 3.0 TDI is mated to an eight-speed tiptronic. An rpm-adaptive torsion damper with a centrifugal force pendulum largely compensates for undesirable vibrations in the engine. This permits efficient driving from engine speeds as low as 1,000 rpm. When coasting and rolling out, a clutch in the central transmission opens and interrupts the power connection. A new electric oil pump makes it possible to engage the gear that will be needed after the rolling phase. The transmission control unit detects stop-and-go situations and ensures very comfortable starts.
The body. Compared to the predecessor model, its interior has grown in length by 21 millimeters (0.8 in). The luggage compartment has a base size of 535 liters (18.9 cu ft) and can be expanded up to 1,390 liters (49.1 cu ft) with the backrests folded down. Body attachments are made of lightweight aluminum. The Gran Turismo gets top marks for stiffness, crash safety, aerodynamics and aeroacoustics.
Chassis. Optional dynamic all-wheel steering combines direct steering with superior directional stability. At the front axle, it changes the steering ratio depending on the driving situation. At the rear axle, it turns the wheels either in the same or opposite direction of the front wheels depending on the speed. Even with the base steering, a new steering boost concept provides the driver with intensive feedback from the road.
The optional sport differential actively distributes drive torque between the rear wheels, complementing the standard quattro all-wheel drive. It, as well as the dynamic all-wheel steering, optional suspension with damper control, optional sport suspension and adaptive air suspension with controlled damping (option), are controlled by the electronic chassis platform (ECP).
Due to this close networking, all systems work together for increased comfort, sportiness and maximum precision. The driver can choose from several profiles in the Audi drive select system; they offer a wider spread between comfort and dynamics compared to the predecessor.
Driver assistance systems. Audi offers a choice of 39 driver assistance systems in the new A7 Sportback. They are split up into three packages: the Park assist package (successive introduction beginning 2018), the City assist package with the new crossing assist, and the Tour assist package.
Like the A8, the new Audi A7 Sportback is equipped with the central driver assistance controller (zFAS), which continually computes an image of the surroundings. It draws on a sensor set that in the full version includes five radar sensors, a laser scanner, a front camera, four 360 degree cameras and twelve ultrasonic sensors.
The Audi (remote) parking pilot and Audi remote garage pilot, which will follow in the course of the year, automatically steer the Gran Turismo into a parking space or garage and back out again when the driver activates and monitors this function on their smartphone. The driver can also activate the Audi parking pilot via the corresponding button.
Digitalization. The new Audi A7 Sportback continues the digitalization strategy begun with the new A8 and adopts the MMI touch response concept with acoustic-haptic feedback: A tangible and audible click confirms activation of a function via the finger on the display. The upper display is used to control the infotainment, while the lower display provides access to the climate control, comfort and convenience functions and text input.Operation is intuitive like on a smartphone.
Audi has designed the optional voice control as a natural language dialogue system (MMI navigation and above). It uses both onboard information as well as knowledge from the cloud to process all input. The driver can also control many functions on the steering wheel, and there is an optional head-up display. MMI navigation plus also includes the Audi virtual cockpit.
MMI navigation uses the latest generation of the Modular Infotainment Platform. It transmits data at LTE speed and features an integrated Wi-Fi hotspot. The navigation system learns from the routes traveled and can make suggestions of its own. The system computes the route online on the servers of the service provider HERE, which considers real-time data for the entire traffic situation.
Among the online services provided by Audi connect are various Car-to-X services, such as traffic sign information and hazard information. The customer can also personalize the system by adjusting some 400 parameters to set up an individual profile for greater comfort and create six more driving profiles. The new Audi A7 already recognizes the customer when the car is opened and adjusts numerous settings according to the individual profile.
With the new digital Audi connect key, the car can also be opened and started with an Android smartphone via Near Field Communication (NFC). The customer can use this key to enable five smartphones or people to access the vehicle. The Audi connect key card in the vehicle is for those situations where the driver has to temporarily give a key to someone else, such as at Audi Service or valet parking.
The four-door coupé rolls off the assembly line at the Neckarsulm site and will launch on the German market in early March 2018.