Audi will soon be introducing the first S model in the Q7 line-up, as the new 435 PS SQ7 TDI joins the range… As the world’s first series production car that combines twin turbocharging with an electrically-powered compressor for a huge power output with immediate response, Audi claims that the new SQ7 TDI ‘consigns turbo lag to history’.
The 2016 Audi SQ7 TDI is powered by a redesigned 4.0-litre V8 BiTDI engine that uses three ’chargers working together , with two exhaustgas turbochargers which are activated selectively according to the concept of sequential charging, with the exhaust gas only flowing through one turbocharger at low and intermediate load and the second turbine 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.
Developing a maximum power output of 435 PS and 900 Nm (664 lb.ft.) of torque, firmly staking its claim as the most powerful diesel SUV on the market, the SQ7 TDI is claimed to be capable of accelerating from 0-62 mph in just 4.8 seconds. The top speed is limited to 155 mph, and the SQ7 TDI returns up to 38.2 mpg combined in the New European Driving Cycle (NED C), corresponding to CO2 emissions of 194 g/km.
Introducing the new model, Dr. Stefan Knirsch, Member of the Board of Management of AUDI AG for Technical Development, said: ‘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’.
Forced induction and 48V electrical system
Placed in the air path downstream of the intercooler, close to the engine, the electric powered compressor (EPC) is a world first in a production vehicle, supporting the 4.0 TDI engine when starting off and accelerating from low load for exceptional take-up with no turbo lag.
Driven by a compact electric motor, its compressor wheel spinning at up to 70,000 rpm, because the EPC doesn’t require any exhaust-gas energy to develop boost it can be used at any time, providing the perfect solution to the traditional weaknesses of the exhaust-gas turbocharger. Consigning ‘turbo lag’ to history, it provides the engine with the boost energy needed for the dynamic delivery of power in less than 250 milliseconds.
The electrical power for the EPC, which reaches a maximum of 7 kW, is provided by the new 48-volt electrical subsystem, which also facilitates the high-power electro-mechanical active roll stabilisation (eAWS) system. To meet the 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 watthours and peak output of up to 13 kW.
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 per cent at an output of up to 3 kW. This is a so-called MOS FET generator (Metal Oxide Semiconductor Field Effect Transistor), which reduces electric losses and increases efficiency. MOS FET s 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.
Audi valvelift system (AVS)
The Audi valvelift system (AVS) is also making its debut in a diesel model from Audi. The inlet and exhaust camshafts 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 enhances 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 so that, overall, the engine produces very good torque delivery and dynamic response across the entire speed range.
The exhaust streams from the two exhaust valves are 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, with the engine achieving its maximum output in this bi-turbo mode. The switching by the AVS enables fast and precise activation of the second exhaust-gas turbine.
Other technical highlights
• The intake side of the 4.0 TDI is on the outside, while the exhaust side with the two turbochargers is on the inside of the 90-degree internal V – a layout that provides for short gas paths for spontaneous response and efficient emissions control.
• The common-rail injection system generates up to 2500 bar of injection pressure, while ignition pressure reaches the 200 bar mark in broad sections of the rev range.
• The innovative thermal management and sophisticated measures in the crankshaft and camshaft drive reduce friction.
• The combination of a NOx oxidating catalytic converter and a downstream SCR catalytic converter, integrated into the diesel particulate filter (DPF) and using AdBlue injection to reduce oxides of nitrogen, results in a particularly efficient emissions control system.
• A sound actuator in the exhaust system amplifies the sound of the engine while the amount of sound it generates can be varied using the Audi drive select system.
Transmission
The redesigned eight-speed tiptronic gearbox in the Audi SQ7 TDI is highly efficient, changing gears extremely quickly and smoothly, and at high speeds it decouples to allow coasting with the engine at idle speed. At the heart of the quattro permanent all-wheel drive system is a self-locking centre differential that is compact, lightweight and interacts very precisely with the suspension control system.
Chassis
Lightweight construction for the suspension includes the use of links made primarily of aluminium, while electro-mechanical power steering, the Audi drive select driving dynamics system and adaptive air suspension with S-specific tuning are standard.
Lightweight carbon fibre-ceramic discs will also become available as options shortly after the market launch. The standard rims are 20-inch alloy wheels with 285/45 tyres, with options up to 22 inches in diameter available soon.
Networked suspension control
Audi will also offer the SQ7 TDI with an optional driving dynamics package comprising three technology modules: sport differential, electro-mechanical active roll stabilisation and all-wheel steering.
The highly integrated suspension control unit used in the SQ7 TDI assumes the central control of the adjustable shock absorbers, the air springs, the sport differential and roll force distribution. With all relevant suspension functions incorporated into a central control unit, optimal networking and co-ordination of the functions has been achieved, providing outstanding handling in any situation.
Body roll stabilisation
The optional electro-mechanical active body roll stabilisation system (eAWS) uses a compact electric motor with a three-stage planetary gearbox which separates the two halves of the anti-roll bar. On uneven road surfaces, they are actively decoupled from one another, resulting in improved ride comfort. During faster driving, the tubes are interconnected and twisted against each other, significantly reducing body roll.
Together with the transmission, the electric motors produce anything up to 1200 Nm (885 lb.ft.) torque, resulting in taut, precise handling, with less body roll in bends and a reduced tendency to understeer. The front and rear anti-roll bars can also be adjusted independently of each other for a positive effect on road behaviour, with the steering precision and the agility of the car also improved significantly.
Compared with conventional hydraulically switched anti-roll bars, Audi’s 48 volt-based system offers major advantages in that it can develop more power, it works faster and it is activated even at low speeds. Because it requires no oil, the electro-mechanical active roll stabilisation is also maintenance-free and environmentally-friendly.
Optional all-wheel steering is also available, with the rear wheels turning by as much as five degrees to make parking easier. The rear wheels can also be steered opposite or in the same direction as the front wheels, improving dynamics and stability. The more direct front-axle steering ratio of the SQ7 TDI also improves the handling characteristics.
Lightweight construction
Thanks to systematic lightweight construction, the Audi SQ7 TDI is the lightest SUV in its segment, without compromising its crash safety. The body features an innovative multimaterial construction using hot-shaped and extremely strong sheets to form the backbone of the occupant cell, while the outer skin is made of aluminium. The centre of mass is low and the drag coefficient is an outstanding 0.34.
Exterior styling
The styling of the SQ7 TDI strikes the right balance between powerful presence and practicality, with unmistakeable features such as the sculpted single-frame radiator grille, distinctively highlighted wheels and flared quattro-style wheelarch blisters.
The 2016 Audi SQ7 TDI has a new radiator grille, with an S specific design for the bumpers, while other distinguishing features are the side air inlets, the door mirror housings and door inlays in standard aluminum. The exhaust system terminates in four rectangular tailpipes.
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LED headlights are fitted as standard, with a pronounced three-dimensional appearance and a double-arrow signature. LED headlights are standard while the Matrix LED headlights and the dynamic rear turn signals are optional. With the LED and Matrix LED headlights, the daytime running lights together with the turn signals form a double light guide arrow – a unique light signature within the Audi family.
The Matrix LED headlights also include intelligent cornering lights, created by a shift in the light centre position and if the car is equipped with the optional MMI navigation plus, the 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, activated when the ignition is turned on, also create a double arrow pattern. The brake light is located in the two upper chambers; the interior of the light has a three-dimensional appearance.
The new SQ7 TDI is available in 12 body colours, with the distinctive radiator grille and underbody guard that encloses the four rectangular tailpipes finished in twilight grey matt.
Interior
Seven seats are standard , with the second row having a three-section backrest with segments that can be folded down separately, the sliding/folding seats also providing easier access to the third row seats which fold up and down electrically.
The SQ7 TDI provides a choice between standard sport seats and optional sport seats plus and a power-operated tailgate is standard. The SQ7 TDI features analogue instruments with grey faces and white needles, special welcome screens and S badges. Interior lighting employs LED s with ambient lighting also available, including illuminated door sill trims and additional contour lighting on the centre console. The top version allows the driver of the SQ7 TDI to customise the interior lighting, using the MMI to adjust it in several profiles and in five zones, and regulate the colour of the contour lighting in 32 steps.
The Audi virtual cockpit, with its 12.3-inch digital display, presents logically structured information in brilliant graphics with excellent driver ergonomics and intuitive operation, with the driver choosing the display mode using the multifunction steering wheel. A head-up display is also available as an option.
The standard MMI navigation plus, with MMI all in touch control, includes a large glass surface on the centre tunnel console that provides the finger with haptic feedback after each click. The MMI logic allows for intuitive system operation and provides voice control.
The top-of-the-line infotainment system in the SQ7 TDI uses the second-generation Modular Infotainment Platform. Thanks to the integrated LTE module included in the Audi connect package, passengers can surf at high speed with their mobile devices. The Audi connect package (a three-month trial is standard, with the option to extend) brings comprehensive online functions on board.
New on the market is the Audi connect safety & service package, which also includes the myCarManager package with which a smartphone can be used to lock and unlock the car or check the vehicle status.
The Audi smartphone interface also provides a tailored environment on the MMI monitor making it easy to control smartphones with iOS or the Android operating system.
There are two optional sound systems: The Bose Surround Sound system, with 19 speakers, also features two speakers located higher up in the A pillars to produce the third dimension. The Bang & Olufsen Advanced Sound System uses a digital signal processor to drives 11 channels with a total of 23 speakers in such a way that the sound is equally precise and harmonious in every seat. Four speakers installed in the A-pillars, driven via separate channels broadcast those elements that generate the spatial height, creating a big virtual stage, while newly developed speakers and a 1920 watt amplifier provide a high quality sound.
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Optional driver assistance systems
The Audi SQ7 TDI 4M offers a wide range of 24 driver assistance systems for safety, fuel-efficiency and comfort. For example, the standard Audi pre sense city anticipatory warning and emergency braking function helps avoid accidents and protects errant pedestrians, while the predictive efficiency assistant provides additional information in the instrument cluster to help the driver save fuel.
Adaptive cruise control with traffic jam assist relieves the driver in slow-moving traffic on well-paved roads by taking over the steering in many situations, while the predictive ACC automatically adjusts driving speed to suit the route and speed limits, such as when entering towns.
We’ll be driving the new SQ7 TDI at the international press launch in early May and will report further in the June issue.
Sport differential
The optional sport differential provides stable and precise steering, particularly during fast acceleration out of bends, thanks to variable torque control between the rear wheels. 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.
Torque shift to the outer wheel to improve cornering performance. Straight ahead: Even torque Distribution. Accelerating out of a bend. Torque shift to the outer wheel to reduce acceleration understter.
‘Placed in the air path downstream of the intercooler, the electric powered compressor is a world first in a production vehicle…’
‘This technology is reserved exclusively for this top Q7 model…’
Wheel-speed sensors (4x). Steering-angle sensor. Central chassis control unit with vehicle dynamic management. Redundant yaw-rate and lateral acceleration sensor systems in the safety computer. Control unit with component software. Sport differential.
