카이미지넷

To coincide with the Los Angeles Auto Show 2014, Audi is inviting international motoring journalists to drive their first few test kilometers on public roads with the technology demonstrator.

“The A7 Sportback h?tron quattro is a genuine Audi – at once sporty and efficient. Conceived as an e?quattro, its two electric motors drive all four wheels,” explained Prof. Dr. Ulrich Hackenberg, Member of the Board of Management for Technical Development at Audi. “The h?tron concept car shows that we have also mastered fuel cell technology. We are in a position to launch the production process as soon as the market and infrastructure are ready.”

In the fuel cell mode, the A7 Sportback h?tron quattro needs only about one kilogram (2.2 lb) of hydrogen to cover 100 kilometers (62.1 mi) – its energy content is equivalent to that of 3.7 liters (1.0 US gal) of gasoline. The tank capacity means it is capable of a range of more than 500 kilometers (310.7 mi).

Like a car with combustion engine, refueling takes no more than around three minutes. The range is boosted by up to 50 kilometers (31.1 mi) by a battery with a capacity of 8.8 kilowatt?hours, which is recharged by recuperation or alternatively from a power socket. As a plug-in hybrid, the A7 Sportback h?tron quattro will thus have crucial extra range in reserve.

The Audi A7 Sportback h-tron quattro 
It sprints from 0 to 100 km/h (62.1 mi) in 7.9 seconds and on to a top speed of 180 km/h (111.8 mph). It covers over 500 kilometers (310.7 mi) on one tank of fuel – and its exhaust emits nothing more than a few drops of water: The A7 Sportback h-tron quattro, which Audi is unveiling at the Los Angeles Auto Show 2014, uses a powerful, sporty electric drive with a fuel cell as its energy source that operates in combination with a hybrid battery and an additional electric motor in the rear. The overall electrical system power of 170 kW is transferred to both the front and the rear wheels. This drive configuration makes the emission-free Audi A7 Sportback* a quattro through and through – a new departure in fuel cell cars.

“The A7 Sportback h?tron quattro is a genuine Audi – at once sporty and efficient. Conceived as an e?quattro, its two electric motors drive all four wheels,” explained Prof. Dr. Ulrich Hackenberg, Member of the Board of Management for Technical Development at Audi. “The h?tron concept car shows that we have mastered fuel cell technology. We are in a position to launch the production process as soon as the market and infrastructure are ready.”

The “h” in the name h?tron denotes the chemical element hydrogen. In visual terms the technology demonstrators that Audi has brought along to the Los Angeles Auto Show basically resemble the production models. As the label with the h?tron signet reveals, this concept car now takes its place alongside the other Audi models with alternative drive principles, the e?tron and g?tron. Externally, there is no other evidence of the fuel cell that converts hydrogen into electrical power on board the vehicle.

The fuel cell
The crucial differences are beneath the hood of the A7 Sportback: The fuel cell in the Audi technology demonstrator is installed at the front, mirroring the conventional A7 Sportback with combustion engine. Because the exhaust system only has to handle water vapor, it is made of weight?saving plastic.

The fuel cell itself comprises over 300 individual cells that together form a stack. The core of each of these individual cells is a polymer membrane. There is a platinum-based catalyst on both sides of the membrane.

This is how the fuel cell works: Hydrogen is supplied to the anode, where it is broken down into protons and electrons. The protons migrate through the membrane to the cathode, where they react with the oxygen present in air to form water vapor. Meanwhile, outside the stack the electrons supply the electrical power – depending on load point, the individual cell voltage is 0.6 to 0.8 volts.

The entire fuel cell operates in the voltage range of 230 to 360 volts. The main auxiliary assemblies include

• a turbocharger that forces the air into the cells,
• the so-called recirculation fan – it returns unused hydrogen to the anode, thus increasing efficiency, and
• a coolant pump.

These components have a high-voltage electric drive and are powered by the fuel cell.

There is a separate cooling circuit for the essential cooling of the fuel cell. A heat exchanger and a thermoelectric, self-regulating auxiliary heating element maintain pleasant temperatures in the cabin.

The fuel cell, which operates across a temperature range of 80 degrees Celsius, places higher demands on the vehicle cooling than an equivalent combustion engine but achieves superior efficiency of as high as 60 percent – almost double that of a conventional combustion engine. Its cold-starting performance is guaranteed down to -28 degrees Celsius.

Plug-in hybrid
A special feature of the A7 Sportback h?tron quattro is its plug?in hybrid concept – this represents a logical evolution from the Audi A2 H2 and Q5 HFC test cars. It has a lithium?ion battery on board that can be recharged from the power socket by lead; with an 8.8 kWh energy capacity, it has been adopted from the A3 Sportback e?tron*. It is located beneath the trunk and has a separate cooling circuit for thermal management.

This high?performance battery makes the ideal partner to the fuel cell. It can store energy recovered from brake applications and supply considerable power for full?load boosting. This paves the way for impressive acceleration, making the A7 Sportback h?tron quattro truly live up to quattro standards. Both the front and rear axles have no mechanical connections for the transmission of power. In the event of slip, the torque for both driven axles can be controlled electronically and adjusted continuously.

On battery power, the Audi A7 Sportback h?tron quattro covers as much as 50 kilometers (31.1 mi). The battery in the rear of the plug?in hybrid can be recharged by lead. Depending on the voltage and current rating, a full recharge takes between two hours (industrial power socket/360 volts) and four hours (domestic power socket at 230 volts).

The battery operates at a different voltage level to the fuel cell. For that reason, there is a DC converter (DC/AC) between the two components. This tri?port converter is located behind the stack. In many operating statuses it equalizes the voltage, enabling the electric motors to operate at their maximum efficiency of 95 percent.

The power electronics in the front and rear of the vehicle convert the direct current from the fuel cell and battery into alternating current for the electric motors to drive the front and rear axles separately.

The two electric motors, which are cooled by a low-temperature circuit together with the voltage converters, are permanently excited synchronous machines. Each of them has an output of 85 kW, or even 114 kW if the voltage is temporarily raised. The peak torque is 270 Newtonmeters (199.1 lb?ft) per electric motor.

The electric motors’ housings incorporate planetary gear trains with a single transmission ratio of 7.6:1. A mechanical parking lock and a differential function round off the system.

The appeal of e-quattro
Driving in the Audi A7 Sportback h?tron quattro offers the full appeal of electric drive in conjunction with the new e?quattro. The silent propulsion is fully available from the off, and the fuel cell reaches its maximum output within one second at full load – a more dynamic response than a combustion engine because the entire drive system involves only a few mechanical components.

With 540 Nm (398.3 lb?ft) of propulsive power at its disposal the Audi A7 Sportback h?tron quattro, which tips the scales at only around 1,950 kilograms (4,299.0 lb), races from a standstill to 100 km/h (62.1 mph) in 7.9 seconds. Its top speed is 180 km/h (111.8 mph) – a top figure for its field of competitors. The e?quattro concept requires precise coordination of the electric motors – the technology demonstrator offers a sporty, stable and high-traction drive that is comparable to a production car with mechanical quattro drive.

A power meter – in the place of the revolution counter in the instrument cluster – informs the driver of the momentary power flow. The outer sections show the fuel level in the hydrogen tank and the level of battery charge. Graphics on the MMI monitor visualize the energy flow. When the driver presses the EV button, the technology demonstrator drives solely on battery power.

Switching from automatic transmission mode D to S increases the level of energy recovery when braking, so that the battery is charged up effectively during sporty driving. Brake applications, too, are almost always accomplished fully electrically: The electric motors then act as alternators and convert the car’s kinetic energy into electrical energy that is stored in the battery. The four disk brakes only become involved if more forceful or emergency braking is required.

The tank flap is in the right side section of the five-door coupé, concealing a filler connector for the hydrogen. Fully refueling with H2 takes around three minutes, roughly as the same as a conventional automobile. The tanks communicate with the refueling system by infrared interface and equalize the pressure and temperature levels.

Zero emissions
The four hydrogen tanks of the Audi A7 Sportback h?tron quattro are located beneath the base of the trunk, in front of the rear axle, in the center tunnel. An outer skin made from carbon fiber reinforced polymer (CFRP) encases the inner aluminum shell. The tanks can store around five kilograms of hydrogen at a pressure of 700 bar – enough to drive over 500 kilometers (310.7 mi). According to the NEDC cycle, fuel consumption is roughly one kilogram (2.2 lb) of hydrogen per 100 kilometers (62.1 mi) – an amount with an energy content equivalent to 3.7 liters (1.0 US gal) of gasoline.

It is already the case that the A7 Sportback h?tron quattro always travels with zero local emissions. By using the renewable fuel hydrogen, it can also be used globally as a zero emissions vehicle: Since 2013 Audi has been operating a pilot plant in which renewable wind power is used to produce hydrogen by electrolysis. At present, this hydrogen is still used in an additional production process to obtain synthetic methane (Audi e?gas). A future move to feed this hydrogen into a hydrogen supply and filling station network would make it available for refueling fuel-cell vehicles. This is a sound option for sustainable mobility with no emissions.

Fuel consumption of the models named above:

Audi A7 Sportback:
Combined fuel consumption in l/100 km: 9.5 – 4.7 (24.8 – 50.0 US mpg)**; 
Combined CO2 emissions in g/km: 221 – 122 (355.7 – 196.3 g/mi)**

Audi A3 Sportback e-tron:
Fuel consumption according to ECE standard in l/100 km: 1.7 – 1.5 (138.4 – 156.8 US mpg)**;
Combined electrical consumption in kWh/100 km (62.1 mi): 12.4 – 11.4**
Combined CO2 emissions in g/km: 39 – 35 (62.8 – 56.3 g/mi)**

**The fuel consumption and the CO2 emissions of a vehicle vary due to the choice of wheels and tires. They not only depend on the efficient utilization of the fuel by the vehicle, but are also influenced by driving behavior and other non-technical factors.

“When he moved to Audi, Marc Lichte launched a design offensive,” says Prof. Dr. Ulrich Hackenberg, Board Member for Development, who brought him to Ingolstadt in 2014. “His clear philosophy and precise understanding of Audi DNA let him develop a design strategy that is opening up entirely new perspectives for us. It is progressive and highly emotional; it expresses the technological competence and quality claim of the brand perfectly. The Audi prologue is its first proponent – it is a ‘signature car’ for Audi.”

Marc Lichte himself describes the character of the show car in this way: “Audi stands for sportiness, lightweight design and the quattro permanent all?wheel drive. In the Audi prologue, we are expressing this know?how in a new form – we have put the sportiest car in the luxury segment on wheels. Our team took new approaches in both exterior and interior design.”

Audi design is now expressing progressive technology even more powerfully. The two?door coupe has a flowing, elegant shape in a sporty and taut design. Its forms and lines are unmistakable and introduce many new ideas. In the clear and unobstructed interior, the architecture melds with the display and operating concept to create a new type of unit. The entire front of the instrument panel is a large touch display, and a portion of the user interface operates with a new type of OLED display made of organic LEDs.

The show car’s technology combines power, comfort and efficiency. The 4.0 TFSI produces up to 445 kW (605 hp) of power and 750 Nm (553.2 lb?ft) of torque; it accelerates the Audi prologue from 0 to 100 km/h (62.1 mph) in 3.7 seconds. Its dynamic all?wheel steering, in which the rear wheels can turn up to five degrees, makes the large couple extremely responsive and stable while driving.

Harmonious proportions: exterior
The Audi prologue is somewhat shorter and flatter than today’s production A8* with a length of 5.10 meters (16.7 ft), wheelbase of 2.94 meters (9.6 ft), width of 1.95 meters (6.4 ft) and height of 1.39 meters (4.6 ft). A dominant feature at its low front end is a Singleframe displaying the four rings that is integrated into the automobile architecture. The large radiator grille has been widened much more, and it is positioned lower than on today’s production models. Its strong horizontal effect expresses an image of powerful dynamics. The cross bars have a finely structured diamond pattern, and their ends are split.

The headlights – shaped like wide, flat wedges – are located with their tips above the Singleframe. They present high-resolution Matrix laser technology: an innovation from Audi which opens up new approaches to headlight design and enables completely new functionalities. The pupils of the headlights are formed by a projection lens with a laser light source – they generate a matrix that illuminates the entire street in high resolution. Hovering beneath this element are five plastic lenses that are supplied with light via a glass fiber bundle, which are mounted to a lightweight structure and further extend the high-beam light. The new laser technology lets lighting designers create an extremely lightweight, compact and elegant eye-shaped form.

Audi quattro DNA visualized
Also new is the sculptural form of the air intakes under the headlights – the distinctive air intakes have diamond pattern screens in their interiors. A dynamically contoured blade, which is clearly separated from the bumper by a gap, elicits associations to motor sport. Mounted to it are two additional spoilers in glossy black, which give the show car an even stronger and wider stance on the road.

In side profile, its flowing silhouette expresses the character of forward motion in the Audi prologue. Balanced proportions put equal emphasis on the front and rear wheels – a clear reference to the quattro DNA of Audi. The powerful 22?inch wheels are set in widely flared wheel arches. They are fitted with tires of size 285/30. Each wheel’s ten intertwining Y spokes project a filigreed, three-dimensional and powerful image.

Edges above the wheel arches refer back to the Ur-quattro
A characteristic feature of the Audi prologue are the flared shoulders above the wheels, front and rear. Like the blisters of the original Audi Ur?quattro of the 1980s, they visualize the quattro drive – but they are no longer just added on, rather they are worked into the flow of the base architecture. In a side view, the shoulders form two gentle arcs above the wheels, which break up the somewhat lower shoulder line between the wheels.

The fenders, doors and rear side panels show curved muscular surfaces. The lower door area has a low concave shape that runs upwards to the rear – a motif that links to the design theme of air inlets. The side sills are drawn inward; glossy black aprons form a continuation of the front spoiler. All lines and surfaces on the Audi prologue show car are logically interrelated, which is typical Audi.

Aluminum components in hand-finished quality
The door mirrors are small aluminum sculptures: The mirror housings in the form of a shell create a flowing transition to the window slot trim. They also integrate the open-door sensor surfaces. The doors have no handles, and they are opened electromechanically when the illuminated sensor surfaces are touched.

Vast areas of the stiff multimaterial body of the Audi prologue consist of aluminum and ultra-high-strength steel. The windows are framed by matt and polished aluminum trim strips. At the end of the low roof dome, the window framing transitions into a solid surface of aluminum; its workmanship illustrates the handcraft-like manufacturing quality of Audi, and it enables lowering of the windows despite the C?pillars. This area integrates the fuel tank lid on the right side of the show car. It has an electric opening mechanism and can be lowered completely into the C?pillar by pressing a button in the interior. For enhanced convenience in refueling, the tank closure does not have a cap. The paint is a light diva gray, a new type of pearl effect paint, which has a warm and elegant appearance.

Rear section drives the whole car forward
The rear section of the Audi prologue also breaks with conventions. It is angled in the driving direction and is reminiscent of the side and rear views of a luxurious yacht; the sickle-shaped seam between the side panel and the bumper emphasizes this dynamism. The edge of the trunk lid, which is executed as a discreet spoiler, picks up on the blister line coming from the side panel. Between the C?pillars, the rear window has a concave inward curve – it closes off the passenger compartment while enabling convenient cargo loading with the separate trunk lid. The Audi prologue unites the positive aspects of a saloon with the aesthetic highlights of a coupe.

The unconventional design of the LED rear lights with their 3D glass gives the tail lights all of the benefits of the new design: the new, long tail lights run across the entire width of the car. At its termination point, the light illuminates the frame of the embossed 3D form. Fine lines in the 3D glass appear to hover in the middle of the light. The brake light is located deep inside the lighting unit. When braking, the bottom of the 3D imprint is also illuminated, which makes the light appear to move towards the observer. This configuration on different levels, and the alternation between 2D and 3D lighting functions lets the observer experience the tail lights in an entirely new dynamic way.

Beneath the bumper, there is a diffuser made of glossy black aluminum; like the front blade, it extends over the full width of the car as a separate, significantly recessed element. The diffuser integrates two trapezoid-shaped inlets which visually coordinate with the embossed tail lights and house the exhaust system tailpipes.

Luxurious and innovative: interior and operating concept
The spacious interior of the Audi prologue is like a luxurious lounge. It is based on Gran Turismo design, and it enables both very sporty driving and relaxed touring. The interface visually adapts to the specific driving style. The interior marks the beginning of a new design era at Audi, in which the architecture merges with the operating concept to form one unit. The surfaces for displays and controls are innovatively integrated into the instrument panel and console of the center tunnel, and the infotainment system brings driver and passenger into dialog with one another.

When entering the vehicle, the four-seat coupe receives its passengers with polite hospitality. The “butler” – an innovative intelligent software program – identifies them based on their smartphones and adjusts the seats and climate control system according to their preferences. The system also makes recommendations for music and route planning that are oriented towards the owner’s preferences. The Easy Slot system, an advanced development of the Audi phone box, is located under lids in the center console. A special mechanism networks the smartphones of passengers to the vehicle infotainment system and charges them.

Generous open interior space
Tautly stretched lines and lean geometric forms give the interior a light and clear ambience. The instrument panel has a light and elegant appearance with its strictly horizontal layout that is not interrupted anywhere, and it emphasizes the generous interior width. It lowers itself towards the interior on two levels. The upper level is positioned, like a roof, above the Audi virtual cockpit future – an advanced development of the Audi virtual cockpit – and above the line of air vents. It is part of the wrap-around – a large arc that encircles the driver and front passenger.

A second wrap-around joins the front and rear sections of the interior and is already quite visible from the exterior. The center console with its pass-through also appears to hover, as do the front seats, whose rails are mounted on the tunnel and side sills. The head restraints of the two rear bucket seats are lowered when not in use; they automatically extend when a passenger enters the rear seating area with the electric easy entry function.

When the sound system is activated, a new type of sound spoiler extends from the rear shelf; it optimally produces a premium sound in the car that is typical of Audi.

Entire front of instrument panel becomes a display
A radically new type of display and operating concept is embedded in the elegant architecture. Across its full width, the front of the instrument panel is designed to be a display surface which integrates three touch displays. The driver-oriented display to the left of the steering wheel is used to control functions for lighting and assistance systems. The driver-oriented operating unit to the right contains media controls. The front passenger faces a widescreen display that is integrated into the full surface of the instrument panel; it is used to individually and conveniently control entertainment features.

The new type of front passenger display enables digital interaction between the driver and front passenger for the first time. A wiping movement by the passenger is all it takes to send pre?configured routes to the driver’s display and input them into the Audi virtual cockpit future.

On the console of the center tunnel, there is a fourth flexible touch display that is ergonomically adapted to the driver; it is used for climate control, handwriting input and other vehicle settings. This display consists primarily of an extremely thin, bendable OLED film (OLED: organic light emitting diodes), and it displays extremely sharp images that are rich in contrast. When not in use, the OLED display is integrated flush to the center console and is nearly invisible. When the car is started, the flexible display stands up. The fact that it bends ensures a constant distance to the hand which makes for better ergonomics. When operating the display, the wrist rests on the low-positioned gear selector lever of the eight-speed tiptronic.

Designers have also redesigned the shift-by-wire lever. It is now integrated seamlessly into the center console. Cupholders and smartphone slots are installed under lids on the center console, to the left and right of the console support element.

Audi virtual cockpit future shows images on three levels
The Audi virtual cockpit future offers a glimpse into the future of the digital cockpit: High-resolution displays and three mirrors generate a virtual stage on three levels – a fascinating view with visual depth. In the navigation view, the first level presents information that is important for driving; levels two and three generate the depth effect in the cockpit. Structuring the information on different levels makes it better organized and easier for the driver to comprehend. The content and colors of the Audi virtual cockpit future change as a function of driving style – in sporty driving, the display switches over to Sport mode with special presentation of the relevant information such as engine rpm, temperatures and charge pressure.

Inside the Audi prologue, every detail clearly illustrates its exclusive character. A finely crafted perforated panel covers the air vents. If the driver sets the blower to a higher stage, the panel retracts downwards.

White LED light conductors trace the distinctive lines of the interior, starting at the doors. A large aluminum brace forms the steering wheel spokes; it harmonizes with the bars on the displays and the door pull handles. All aluminum accents show perfection in craftsmanship: Their surfaces have matt finishes, and the edges are polished – a fine interplay of gloss levels.

Natural materials communicate a new luxury
For Audi designers from the Color & Trim area, natural materials are the new luxury; all of the materials in the show car fascinate with their authenticity. The surfaces of the seats and seat backs, the dashboard, the console on the center tunnel and the armrests are covered in light-colored “passion” leather – a new soft grade of leather that emphasizes the natural characteristics of the animal hide.

Soft nubuck leather, also in a light color, covers the backs of the seats and the side panel trim of the rear seating area. On the instrument panel, the gray-brown trim of the lower section provides another strong accent. The wrap-around is upholstered in dark “passion” leather; here, and in many other areas, aluminum trim strips contrast with panels of open-grained silver-gray elm wood veneer.

Sporty yet convenient: the technology
The technology of the Audi prologue is as sophisticated as its interior is emotion-evoking. The 4.0 TFSI, which is installed in the engine compartment like a technical masterpiece, produces 445 kW (605 hp) and 700 Nm (516.3 lb?ft) of torque; in overboost mode, which the driver can call up for around 15 seconds, a boosted torque of 750 Nm (553.2 lb?ft) is available. The sonorous biturbo V8 accelerates the two?door coupe, which has an unladen weight of 1,980 kilograms (4,365.2 lb) from 0 to 100 km/h (62.1 mph) in 3.7 seconds.

The show car’s combined fuel consumption is just 8.6 liters per 100 kilometers (27.4 US mpg), which equates to CO2 emissions of 199 grams per kilometer (320.3 g/mile). One contributor to this high efficiency is a new 48?volt subsystem of the vehicle electrical system – this is a technology that will soon be introduced to production cars at Audi. The 48?volt system is supplied by a powerful belt starter generator, which turns the powertrain into a mild hybrid and has an energy recovery output of up to 12 kW during braking. An eight?speed tiptronic directs engine power to the quattro permanent all-wheel drive, which works closely with torque vectoring.

New five-link wheel suspensions
In the chassis, the adaptive air suspension sport – an air suspension with controlled damping – offers a large adjustment range between smooth rolling and very tight handling; it also varies the show car’s ground clearance over several levels. The front and rear suspensions are engineered as lightweight five-link designs. The large carbon-fiber ceramic brake discs decelerate the show car powerfully. On the 20?inch front brakes, they are gripped by six-piston fixed calipers.

A technology highlight of the Audi prologue is its dynamic all-wheel steering – it boosts driving dynamics and ride comfort by an intelligent combination of dynamic and all-wheel steering. The driver therefore can enjoy an automobile with extremely good handling. In the lower speed range, this is made evident by better agility and turning ability. In the higher speed range, developers improved the car’s responsiveness which leads to greater vehicle stability.