Biturbo V8-engined SQ7 TDI pushes boundaries with compressor-enhanced performance and electromechanical active roll stabilisation
- First Audi S model in the Q7 lineup, and the second ever S-specific Audi SUV
- Electric powered compressor is a world first on a production car
- Supplements 435 PS and 900Nm from the V8 BiTDI at the disposal of the driver
- 0-62 mph in just 4.8 seconds, 155mph governed top speed
- Pricing to be confirmed closer to expected start of UK ordering in May – first deliveries will begin in August
- Also new at Audi: high-performance, 48-volt electrical subsystem and electromechanical active roll stabilisation
- The most powerful diesel SUV on sale, developing 435 PS and 900 Nm
- Audi valvelift debuts in the diesel engine
- Seven seats, S body styling, 20-inch alloy wheels, all-LED headlights, MMI navigation plus with MMI Touch, adaptive S air suspension, Audi pre sense city and a powered tailgate fitted as standard
Ingolstadt, March 3, 2016 – Tapping into extra accelerative power becomes as quick and easy as flicking a light switch this week as the new 435PS Audi SQ7 TDI joins the range as the world’s first series production car combining turbocharging with an electrically powered compressor bringing breathtakingly immediate response. Consigning ‘turbo lag’ to history, the boundary-stretching technology underscores the newcomer’s eligibility for the ‘S’ badge that denotes extraordinary performance across the Audi range, and fittingly goes hand-in-hand with another major forward stride in dynamics – electromechanical active roll stabilisation for significantly reduced body roll.
At the heart of the new Audi SQ7 TDI is a redesigned V8 BiTDI engine that now develops 435 PS and 900 Nm (663.8 lb‑ft) of torque, firmly staking this performance flagship’s claim as the most powerful diesel SUV on the market. The electrically powered compressor dispenses with any sign of turbo lag from step-off acceleration, helping to set an outstanding 0-62 mph sprint time of just 4.8 seconds. Top speed is limited to 155mph, and in the New European Driving Cycle (NEDC), the SQ7 TDI returns up to 38.2 mpg combined. This corresponds to CO2 emissions of 194 g/km.
“Following the launch of the successful SQ5, we are now also applying the concept of a diesel-engined S model to the Q7 model line. So equipped, the SQ7 TDI with a V8 TDI engine achieves the consumption figures of a six-cylinder. The new technology solution of the electric powered compressor in the SQ7 TDI is a world first in the competitive environment, with which Audi once again underscores its claim Vorsprung durch Technik,” said Dr. Stefan Knirsch, Member of the Board of Management of AUDI AG for Technical Development.
Forced induction: Three chargers working together
The 3,956cc 4.0 TDI has been redesigned from the ground up. It combines best-in-class performance with impressive efficiency credentials through the use of two exhaust-gas turbochargers which are activated selectively according to the concept of sequential charging, since exhaust gas only flows through one turbocharger at low and intermediate load. The second turbine is only activated at higher loads. The electrically powered compressor (EPC) augments the work of the two turbochargers, particularly in the lower engine speed range, providing for extremely responsive off-the-line performance.
Forced induction concept and electrical system: Electric powered compressor (EPC) and 48‑volt subsystem
The electrically powered compressor is a world first in a production vehicle. This EPC strongly supports the 4.0 TDI engine when starting off and accelerating from low load for exceptional take-up with no turbo lag. It is placed in the air path downstream of the intercooler, close to the engine. Because the EPC does not require any exhaust-gas energy to develop boost, it can be used at any time, thus making it the solution for the traditional weaknesses of the classic exhaust-gas turbocharger. With this technology, turbo lag is history.
The EPC provides the engine with the boost energy needed for the dynamic delivery of power in less than 250 milliseconds. Driven by a compact electric motor, its compressor wheel spins up to 70,000 revolutions per minute. The 4.0 TDI thus develops its immense power immediately, with no perceptible lag.
The Audi valvelift system (AVS) is also making its debut in a diesel model from Audi. The inlet and exhaust cam shafts each have two cam contours per valve. On the inlet side, one cam contour supports starting off in conjunction with the EPC, while the other optimises cylinder filling and thus power at high engine speeds. The AVS system on the exhaust side enables activation of the second exhaust-gas turbocharger. The sequential charging system controls the two exhaust-gas turbochargers so that only one turbocharger is used at low engine speeds. The second is activated additionally at higher loads and engine speeds. The customer benefits from very good torque delivery and dynamic response across the entire engine speed range.
The exhaust streams from the two exhaust valves are hermetically separated, with each driving one of the two turbochargers. In the lower engine speed range, one valve per cylinder remains closed, so that the full exhaust stream flows to the active turbocharger. When load and engine speed increase, the AVS opens the second exhaust valves. This directs flow to and activates the second exhaust-gas turbocharger. The engine achieves its maximum output in this biturbo mode. The switching by the AVS enables fast and precise activation of the second exhaust-gas turbine.
The power for the EPC, which reaches a maximum of 7 kW, is provided by the 48‑volt electrical subsystem. The SQ7 TDI uses this higher-power electrical system, which facilitates the high-power systems electromechanical active roll stabilisation (EAWS) and EPC. To meet their high power and energy requirements, the electrical subsystem includes its own 48‑volt lithium-ion battery mounted beneath the luggage compartment with a nominal energy content of 470 watt-hours and peak output of up to 13 kilowatts. A DC/DC converter connects the 48‑volt and 12‑volt electrical systems. The required energy is provided by a more powerful and highly efficient generator with an efficiency of over 80 percent at an output of up to 3 kW. This is a so-called MOSFET generator (Metal Oxide Semiconductor Field Effect Transistor), which reduces electric losses and increases efficiency. MOFSETs replace the diodes used previously. In addition, the 48-volt storage unit supports the 12‑volt electrical system when required. This also reduces the load on the 12-volt lead battery.
V8 TDI – further technical highlights
The intake side of the 4.0 TDI is on the outside, the exhaust side with the two turbochargers is on the inside of the 90-degree internal V. This layout provides for short gas paths, i.e. spontaneous response and short paths for the emissions control system. The common-rail system generates up to 2,500 bars of injection pressure. Ignition pressure reaches the 200‑bar mark in broad sections of the characteristic.
The innovative thermal management and sophisticated measures in the crankshaft and camshaft drive reduce friction. With the combination of a NOx oxidating catalytic converter and a downstream SCR catalytic converter, which is integrated into the diesel particulate filter and uses AdBlue injection to reduce oxides of nitrogen, the V8 TDI has a particularly efficient emissions control system. A sound actuator in the exhaust system amplifies the sonorous eight-cylinder sound and SQ7 TDI drivers can vary the amount of sound it generates using the Audi drive select system.
The biturbo V8 combined with the EPC is a core element of the global Audi diesel strategy. With high torque even at low engine speeds and low consumption figures, it is also ideally suited for markets such as the United States. Its engine characteristic combines supreme pulling power with impressive agility, exceptional step-off performance and spontaneous response.
High efficiency: The eight-speed tiptronic
The 4.0 TDI in the Audi SQ7 TDI works with strong partners, including a redesigned eight-speed tiptronic which is impressively efficient. It changes gears extremely quickly and efficiently, and at high speeds allows coasting at idle. A self-locking centre differential is the heart of the quattro permanent all-wheel drive system. It is compact, lightweight and interacts very precisely with the suspension control system.
The maxim of lightweight construction also applies to the suspension – its links are made primarily of aluminium. Electromechanical power steering, the Audi drive select driving dynamics system and adaptive air suspension with S-specific tuning are standard. Extremely lightweight carbon fibre-ceramic discs will also become optionally available shortly after the market launch. Audi offers the SUV with 20‑inch wheels on 285/45 tyres, with options up to 22 inches from quattro GmbH available soon after UK ordering opens.
Networked suspension control
Audi offers the SQ7 TDI with an optional driving dynamics package comprising three technology modules: sport differential, electromechanical active roll stabilisation and all-wheel steering. The highly integrated suspension control unit is used in the SQ7 TDI. It assumes the central control of the adjustable shock absorbers, the air springs, the sport differential and roll force distribution. By incorporating all relevant suspension functions into a central control unit, the developers achieved an optimal networking and coordination of the functions among themselves. The customer thus experiences outstanding handling in any situation.
Body roll stabilisation
A new solution in the competitive environment is the optional electromechanical active body roll stabilisation. Here a compact electric motor with a three-stage planetary gearbox separates the two halves of the stabiliser. On an uneven road surface, they are actively decoupled from one another, resulting in improved ride comfort. During faster driving, the tubes are interconnected and twisted against each other. That significantly reduces body roll, i.e. the lean of the car. Together with the transmission, the electric motors produce anything up to 1,200 Nm (885.1 lb‑ft) torque. The effect is taut, precise handling: The car leans less in bends and the tendency to understeer is further reduced. The front and rear stabilisers can be adjusted independently of each other. This active distribution of forces between the front and rear axle has a positive effect on road behaviour. Steering precision and the agility of the car improve significantly.
Compared with conventional hydraulically switched stabilisers, the 48‑volt-based system from Audi offers major advantages. It can develop more power, it works faster and it is activated even at low speeds. Because it requires no oil, the electromechanical active roll stabilisation is also maintenance-free and environmentally friendly.
Bold road behaviour and handling: optional All-wheel steering
With all-wheel steering, the rear wheels turn in by as much as five degrees, making parking easier. The more direct front-axle steering ratio of the SQ7 TDI improves the handling characteristics. Depending on the situation, the rear wheels steer opposite or in the same direction as the front wheels, improving dynamics and stability.
High agility in every bend: quattro with optional sport differential
The optional sport differential provides stable and precise steering, particularly during fast acceleration out of bends. Variable torque between the wheels on the rear axle offers supreme control in curves. The SQ7 TDI is pressed precisely into the bend as a result. Even if the rear end starts to swing out, the quattro sport differential brings it back under control. This technology is available for the first time in the Q7 model range and is reserved exclusively for this top model.
Lightweight construction – innovative multimaterial construction
Thanks to systematic lightweight construction, the Audi SQ7 TDI is the lightest SUV in its segment, yet makes no compromises with respect to crash safety. The body features an innovative multimaterial construction. Hot-shaped and extremely strong sheets form the backbone of the occupant cell; the outer skin is made of aluminium. The centre of mass is low – another factor for the immersive handling. The drag coefficient is an outstanding 0.34.
Powerful and purposeful: Exterior styling
The new Audi SQ7 TDI strikes an impressive balance between powerful and intensified stylistic elements. At 5.07 metres, it is approximately as long as the standard Q7 SE. The Audi DNA, such as the sculpted Singleframe radiator grille, distinctively highlighted wheels and flared quattro-style blisters, is unmistakable. All lines and surfaces are designed precisely and incisively, and accentuate the width of the car and thus the solidness of the overall concept. The SQ7 TDI has a new radiator grille with an S‑specific design at the bumpers. Other distinguishing features are the side air inlets, the mirror housings and door inlays in standard aluminum. The exhaust system terminates in four rectangular tailpipes.
LED headlights fitted as standard
The headlights have a pronounced three-dimensional appearance overall with a double-arrow signature. The standard LED and optional Matrix LED headlights plus the dynamic rear turn signals underscore Audi’s leading role in lighting design and technology. With the LED and matrix LED headlights, the daytime running lights together with the turn signals form a double light guide arrow – a new and unique light signature within the Audi family. Each Matrix LED headlight divides its high beam into 30 individual light-emitting diodes paired with three reflectors. A camera on the interior mirror analyzes the traffic situation. Given this information, the control unit individually turns the diodes on and off, or dims them in 64 stages each, depending on the situation. With the millions of different resultant beam patterns, the high-end headlights superbly light up the road, without blinding other road users. Traffic signs are illuminated with less power so that the driver is not blinded by glare.
The functional range of the Matrix LED headlights also includes intelligent cornering lights, created by a shift in the light center position. If the car is equipped with the optional MMI navigation plus, this system’s route data will trigger the cornering light to illuminate around the corner just before the driver begins turning the steering wheel. The large LED rear lights vary the theme of the headlamps: The tail lights, activated when the ignition is turned on, create a double arrow like the headlights. The brake light is located in the two upper chambers; the interior of the light has a three-dimensional appearance, with lightness and elegance.
There seems to be no end to the onslaught of SUV’s jumping out from almost every car manufacturer, Audi themselves released the Q2 only the other day and this week SEAT and Toyota with the C-HR have thrown their hats into the crossover ring as well.