GENEVA: At the 2017 Geneva Motor Show advanced Electrically Powered Compressor (EPC) technology first used by Audi in the SQ7 TDI is flexing its muscle in a TFSI petrol engine for the first time in the Audi Q8 sport concept.
Demonstrating the vision Audi’s developers and designers have for the dynamic yet efficient SUV of tomorrow, the latest Q8 study combines its EPC with a six-cylinder TFSI and a mild hybrid system – a world first that enables it to deliver an exceptional 476PS output with the efficiency of a four-cylinder equivalent.
Augmented by the compressor and Mhev system the 3.0 TFSI engine powers the Q8 sport concept from 0 – 62mph in just 4.7 seconds and keeps going until it reaches its top speed of 170mph.
Meanwhile, its range of more than 745 miles ensures it is also suitable for long journeys. Thanks to the superb recuperation performance of 20 kW, this imposing SUV holds a considerable fuel economy advantage over a model equipped with a regular TFSI six-cylinder engine without mHEV system, and its CO2 output also shows a 25 g/km improvement.
“The drive system of the Audi Q8 sport concept is a major step towards optimising efficiency and sustainability in large-volume series production. The combination of mild hybrid technology and a TFSI engine sets a new benchmark for the synthesis of electromobility and combustion engines. In the future, this combination will be used in many Audi models,” says Rupert Stadler, Chairman of the Board of Management at AUDI AG.
Highly efficient power package: the drive system
The architecture of the drive system in the new Audi Q8 sport concept is revolutionary: for the first time ever, Audi is combining a 450PS 3.0 TFSI six-cylinder engine with an electric powered compressor and an effective mild hybrid system for recuperation.
The starter generator positioned between the crankshaft and the transmission handles recuperation and, if required, can work in the opposite direction as an additional electric motor. The 48-volt electrical system assures the supply of electrical power.
For the customer, this approach has a number of advantages: the energy recovered as part of recuperation can, if required, be used to increase performance.
During boost operation – where the combustion engine and electric motor are used simultaneously – the electric motor’s additional 20 kW of output and its torque of 170Nm open up a total of 350 kW of power to the engine and bring its total torque up to 700Nm.
The result is forceful acceleration at any speed and any point in the rev range.
Positioned at the rear under the luggage compartment, the lithium-ion battery with an energy storage capacity of 0.9 kWh makes it possible to keep moving slowly in stop-start traffic with the combustion engine switched off, as well as allowing for manoeuvres and parking under electric power alone.
During braking, efficient recuperation using the 20-kW-strong starter generator quickly recharges the battery to ensure that the vehicle can regularly be driven under electric power.
In addition to the two exhaust gas turbochargers, the electric powered compressor provides the Q8 sport concept with an additional kick by supplying the three-litre six-cylinder engine with fresh air. The electric powered compressor supports the turbochargers at times when the exhaust gas is insufficient for rapid development of power.
It therefore opens up delay-free acceleration to the V6 petrol engine – something previously only known to diesel engines and electric motors. It’s a recipe for success which already works impressively in the series production Audi SQ7.
The electric powered compressor is positioned in a bypass downstream of the intercooler, i.e. close to the engine. Instead of the turbine wheel, it integrates a compact electric motor. It accelerates the engine’s compressor wheel up to 70,000 rpm in less than 250 milliseconds.
With the support of the electric powered compressor, the power of the 3.0 TFSI is always rapidly available as soon as the accelerator is depressed, even at low engine speeds. When driving off, the SUV immediately takes a lead of several metres ahead of the competition. During comfort-oriented driving, the electric powered compressor technology prevents unnecessary downshifts and thus keeps the engine speed at a low level. Meanwhile, keen drivers will appreciate the instantaneous delivery of power when exiting corners.
The Q8 sport concept drive system with its V6 TFSI and additional electric motor supplies the performance of a true eight-cylinder engine, yet with the fuel consumption of a frugal four-cylinder. That’s because, compared with a similar engine without mild hybrid system, the consumption reduces by more than a litre per 100 kilometres, despite serving up 20 kW of additional power. The total range of the Q8 sport concept equipped with an 85-litre fuel tank is more than 745 miles.
High-tech from production models: drivetrain and suspension
In the Audi Q8 sport concept, the quattro permanent all-wheel drive system transfers the power of the drive system to the road with supreme control. Even for its wide-track chassis, the technology study makes use of the latest high-end solutions from the luxury-class product portfolio.
The adaptive air suspension sport – an air suspension system with controlled damping – allows for a broad spectrum of ride characteristics, ranging from cushioned cruising to firm and tight handling. Furthermore, it sets the ground clearance in five levels with 90-millimetre height differences, selecting the ideal level in each case. The front and rear axles are engineered as lightweight five-link constructions.
Audi mounts 305/35 tyres on the large 11J x 23 wheels. The five intertwining Y-spokes project a powerful image. Ceramic brake discs measuring 20 inches in diameter effortlessly decelerate the Audi Q8 sport concept.
Dynamic lines and high-tech design details
At first glance, it is clearly a highly dynamic and luxurious Audi – that’s how the Audi Q8 concept study was received at the 2017 Detroit Motor Show. The debutant in Geneva is an even more sporty variation of this composition and is also an elegant alternative to the robust presence of a classic Sport Utility Vehicle. The Q8 and Q8 sport concept are synonymous with prestige and technology in all areas.
At 5.02 metres long, the Audi Q8 sport concept makes an impressive mark on the luxury class. Thanks to a wheelbase of three metres, the show car offers plenty of space for passengers and luggage. Despite the sloping, coupe-like roofline, even the rear-seat passengers enjoy ample head and shoulder room. The new operating concept uses large touchscreens in the cockpit, rounded out by an expanded version of the Audi virtual cockpit and a contact-analogue head-up display. The latter uses intelligent augmented reality technology that merges the real and the virtual worlds.
Viewed from the front, the 2.05 metre wide Audi Q8 sport concept looks imposing. A distinguishing feature here is the octagonal Singleframe grille. It is a sculpted piece and is significantly wider than in today’s Audi production models. Its surface has a honeycomb lattice structure overlayed with aluminium segments, whilst the surround is painted in a contrasting colour. As is typical of Audi Sport models, the outer air inlets are much larger compared with the basic model – a sign of the greater air requirements of the high-performance power unit. A distinctive body-coloured blade forms the bottom edge of the bumper.
The flat, wedge-shaped headlights of the Audi Q8 sport concept are integrated into the front end and, from a design perspective, are connected with the adjoining air inlets. The individual light elements have a glass cover, but the entire headlight units are not enclosed. This creates the impression that they are free in space.
Keyword: 2017 Geneva Motor Show: Audi Q8 sport concept pops in