Companywide substainability

Sustainability is one of the cornerstones of the Audi Strategy 2025. It is becoming an increasingly important issue for the customer and is a political imperative. One element of the corporate philosophy is to minimize environmental pollution and conserve natural resources. At the same time, Audi ensures that materials are processed carefully whilst also maintaining high quality standards. At the Audi Summit, the brand is demonstrating just how attractive the concept of sustainability can be – both in terms of production activities and the products themselves.

1. High tech in the service of efficiency
Drop by drop, gram by gram: Audi has been using high-tech solutions to reduce the fuel consumption of its vehicles for years. The latest innovation is the mild-hybrid technology with which Audi is driving the electrification of its drive systems. In addition, numerous models benefit from quattro with ultra technology and lightweight construction using Audi Space Frame (ASF) technology.

1.1 Versatile: mild-hybrid technology
Audi is pressing ahead with the electrification of its drive systems across a broad front. In mid-2017, the new mild-hybrid drive vehicles (MHEVs) will start joining the product line. The next generation of luxury sedans, the Audi A8, will have them on board – in the 48-volt version – regardless of engine type.

The new technology is suitable for the interplay with either diesel or gasoline engines and can reduce consumption of a V6 gasoline engine by up to 0.7 liters per 100 kilometers (0.2 US gal per 62.1 mi) in real-world driving, for example. Unlike other efficiency technologies within the engine, the MHEV drive systems increase ride comfort, since they allow silent coasting within larger speed ranges of up to 160 km/h (99.4 mph).

Audi offers the MHEV drives in two variants. For the four-cylinder engines, they are based on the familiar 12-volt electrical system. The six-cylinder and eight-cylinder engines will receive a new 48-volt system generally serving as the main vehicle electric system. In particular, this technology offers many ways for making driving more efficient, sportier and more comfortable in the future.

At the 2017 Geneva Motor Show the brand presented the potential of its new technologies in the form of the Audi Q8 sport concept show car. Its 48-volt electrical system integrates a further developed MHEV system as well as an electric-powered compressor (EPC).

Together the two components provide a new level of dynamics. The efficiency is also significantly increasing – at low speeds as in parking, the show car can even be driven electrically.

MHEV: the operating principle
The mild-hybrid drive from Audi in the new A8 comprises two central components. One is a water-cooled belt alternator starter (BAS) on the front side of the engine. A heavy-duty V-ribbed belt connects it to the crankshaft. The BAS yields a recuperation level up to 12 kW and 60 Nm (44.3 lb-ft) of torque.

The second component is a lithium-ion battery with 10 Ah charge capacity and a constant voltage of 48 volts. In the new large sedan, the newly developed 48-volt power system serves as the main vehicle electrical system. The 12-volt system is connected to the main electrical system via a DC/DC converter. Located in the luggage compartment, the lithium-ion rechargeable battery is about the size of a large lead battery. Controlled air cooling provides the thermal management.

The 48-volt-based MHEV technology is particularly more comfortable and efficient. If the driver takes his/her foot off the accelerator at a speed between 55 and 160 km/h (34.2 to 99.4 mph), the car can coast for up to 40 seconds with the engine off completely. During slow coasting, the start-stop phase already begins at 22 km/h (13.7 mph).

Once the driver accelerates again – whether from a stop or while driving – the vehicle restarts quickly and very comfortably: the BAS revs up the internal combustion engine to the target speed, then injection occurs again and, in the case of a gasoline engine, ignition. While the conventional pinion starter remains on board, it essentially is used only for initial starting, when the engine oil is still cold and viscous.

In many situations, recuperation – recovery of energy during deceleration – is more efficient than coasting. To make this decision, the drive management system in the new Audi A8 uses the front camera and, optionally, data from the predictive efficiency assistant, the route data stored in the navigation system and other data supplied by the highly networked sensor set. The bottom line is that the mild-hybrid drive achieves fuel savings of up to 0.7 liters per 100 kilometers (0.2 US gal per 62.1 mi) in real-world driving (with the V6 TFSI).

Audi also offers the new MHEV technology with the conventional 12-volt electrical system. In this configuration, it interacts with the 2.0 TFSI engine. The functional principle is the same as with 48 volts, although the coasting phases, recuperation output and the CO₂ savings are somewhat smaller.

Broad base: 48-volt on-board electrical system
In a different layout – without MHEV functionality – the 48-volt system already entered volume production in 2016 in the Audi SQ7 TDI (combined fuel consumption in l/100 km: 7.6 – 7.2 (30.9 – 32.7 US mpg); combined CO₂ emissions in g/km: 199 – 189* (320.3 – 304.2 g/mi)). In this vehicle, the alternator still operates on a 12-volt basis, and a DC converter couples the 48-volt electrical subsystem. It in turn supplies the electric-powered compressor (EPC) for the V8 diesel as well as the electromechanical active roll stabilization (eARS).

The EPC supports the two turbochargers of the 4.0 TDI engine with up to 7 kW of power whenever they cannot draw enough energy from the exhaust stream. The power is immediately available when the driver accelerates – the experience is particularly impressive when starting off. The eARS is another innovation from Audi. Its centerpiece is an electric motor that uncouples the two halves of the stabilizer when driving straight ahead. The result is excellent ride comfort. During sporty driving along bends, the electric motor turns the stabilizer tubes towards one another, for greater tautness in handling.

Audi is now taking great strides in introducing the 48-volt and MHEV technologies into volume production. In a few years, other Audi model series will also be receiving the new mild hybridization scope. The new architectures allow the realization of even greater power and torque, and innovative features will enable greater fuel savings.

In the medium term, the brand plans to convert ancillary units like pumps and compressors to 48 volts; they will then be able to be more precisely controlled according to requirements, as well as them having a lighter and more compact construction. The same applies to large static convenience consumers such as window heating or sound systems. Small consumers such as control units or lights will remain in the 12-volt system well into the future, however.

Electrical coasting, powerful boosting: Audi Q8 sport concept
The brand has demonstrated the great potential of MHEV systems with its Audi Q8 sport concept car, which made its debut at the 2017 Geneva Motor Show. Located between the crankshaft and transmission, the starter alternator outputs 20 kW and 170 Nm (125.4 lb-ft). During deceleration, the powerful MHEV system can recover a high measure of energy and feed it back into the lithium-ion battery. At low speeds, it can drive the sports SUV by itself. Boosting by the internal combustion engine, a 3.0 TFSI, affords a total of up to 700 Nm (516.3 lb-ft).

The 48-volt system of the Audi Q8 sport concept features an electric-powered compressor (EPC) in addition to the integrated starter alternator. It closes the turbo lag and allows for a large and powerful mono twin scroll turbo. With a system output of 350 kW (476 hp), the show car accelerates from zero to 100 km/h (62.1 mph) in 4.7 seconds, and presses ahead to a top speed of 275 km/h (170.9 mph). The MHEV system lowers fuel consumption of the concept car by approximately one liter per 100 kilometers (0.3 US gal per 62.1 mi).

1.2 Permanently available: quattro with ultra technology
quattro drive revolutionized Audi and continues to characterize the brand with the four rings. It was born in the winter of 1976/77 during test drives in the deep snows of Sweden. Audi engineers developed the quattro system as all-wheel drive for sporty cars. The original quattro, the first Audi production model with quattro drive, debuted in 1980. Audi has continuously refined the technology over the decades – from a manually locking center differential to various types of self-locking center differentials. The developers are constantly optimizing these systems for dynamics and traction.

In 2016, the brand brought a trendsetting innovation to its production vehicles: quattro with ultra technology. This optimized all-wheel drive system is particularly efficient because it engages only when required. Despite this, the drive system exhibits no perceptible differences from permanent systems in terms of traction and driving dynamics.

The ultra technology reduces fuel consumption significantly. During test drives in normal traffic, the developers achieved average fuel savings of 0.3 liters per 100 kilometers (0.1 US gal per 62.1 mi) compared with a conventional all-wheel drive system. The conventional system, in turn, consumes roughly 0.5 liters (0.1 US gal) more than a front-wheel drive vehicle. This means that quattro with ultra technology reduces the added consumption associated with all-wheel drive by around 60 percent.

During moderate driving, quattro with ultra technology enjoys all the advantages of front-wheel drive. All-wheel drive remains permanently available however, and is there immediately when needed. The control system for the quattro powertrain is comprehensively networked. It acquires and evaluates data – in ten millisecond cycles – such as the steering angle, transverse and longitudinal acceleration and engine torque.

All-wheel drive is generally activated predictively, i.e. in anticipation of the need for it. For example, the control unit computes the point when the inside front tire will reach the limit of grip during fast cornering. The calculation is made roughly half a second in advance. Shortly before the wheel reaches the calculated traction limit, the all-wheel drive is activated. With reactive activation – which rarely occurs in practice – the system reacts to sudden changes in the coefficient of friction. These changes might occur, for example, when the wheels go from dry asphalt to a sheet of ice. Thanks to the very short switching times, full quattro performance is ensured even in these extreme situations.

The concept with two clutches in the powertrain gives quattro with ultra technology a key efficiency advantage over the competition. When the system changes to front-wheel drive, the front clutch – a multi-plate clutch at the transmission output – disconnects the propshaft. A decoupling clutch also opens in the rear differential. It shuts down the rotating components that cause the most drag losses here, such as the large crown wheel running in the oil bath. Despite the additional components, the quattro with ultra technology is nearly four kilograms (8.8 lb) lighter than the previous system.

The efficiency-optimized all-wheel drive system is currently available for many engine variants of the Audi A4, A5 and Q5. Other models will soon follow. The system can be used in combination with the manual transmission and the S tronic dual-clutch transmission on models with torque values of up to 500 Newton meters (368.8 lb-ft).

In 2016, 44 percent of all customers worldwide chose a quattro drive. It is most popular in the USA, Canada, Russia and the markets in the Middle East. In January 2017, the eight millionth Audi with quattro drive drove off the assembly line – a Q5.

The classic quattro technology is available in all model series, but there are conceptual differences between them. For example, the quattro drive used in the S1 (combined fuel consumption in l/100 km: 7.2 – 7.0* (32.7 – 33.6 US mpg); CO₂ emissions in g/km: 168 – 162* (270.4 – 260.7 g/mi)), Q2, A3, Q3 and TT features a hydraulically actuated, electronically controlled plate clutch on the rear axle. In the Audi R8, the multi-plate clutch is installed on the front axle.

Depending on the engine/transmission variant, models based on the modular longitudinal platform – the Audi A4, A5, Q5, A6, A7, Q7 and A8 – have either quattro drive with a self-locking center differential or quattro with ultra technology. The Audi Q7, A4 allroad quattro and A6 allroad quattro as well as the Audi A8 and R8 (combined fuel consumption in l/100 km: 12.3 – 11.4* (19.1 – 20.6 US mpg); combined CO₂ emissions in g/km: 287 – 272* (461.9 – 437.7 g/mi)), not mention all S and RS models are equipped as standard with the quattro drive system.

1.3 Lightweight construction: a driving force for Audi
The best material in the best place. This is one way of achieving a sustainable advantage that will also benefit the customer. Less weight and greater rigidity improve safety, the efficiency of the car and its sporty performance. 

Audi is both a pioneer and a driver of innovation in the field of lightweight construction. The brand with the four rings acquired this worldwide reputation with the first generation of the A8. Vorsprung that has won many enthusiastic followers. The self-supporting aluminum body based on the Audi Space Frame (ASF) has shown off its advantages in truly sustainable fashion. Since 1994 Audi has built and sold more than one million production cars in ASF design. And now this successful technology is about to take a decisive step forward.

The material mix in the new Audi A8
The next generation of the A8 is yet again delivering Vorsprung to its owners thanks to an intelligent mix of four materials: aluminum, steel, magnesium and carbon-fiber-reinforced polymer (CFRP) are taking multi-material construction in the Audi Space Frame to a new level for the next generation of the A8. It’s not just the weight that is optimized by this mix. The torsional rigidity of the A8 surpasses that of its predecessor by up to 24 percent. A key parameter for precise handling and acoustic comfort.

A high-strength combination of CFRP and hot-formed steel components make up the occupant cell. Some of these sheet metal blanks are manufactured in varying thicknesses, while others also undergo partial heat treatment. That reduces weight and increases the strength, especially in areas of the vehicle that are particularly critical for safety.

Aluminum components in the form of cast nodes, extruded profiles and sheets – elements characteristic of the ASF design – make up the biggest share of the new Audi A8 body, at 58 percent. New heat-treated cast alloys attain a tensile strength of over 230 MPa (megapascals) – a much higher figure than previously achieved. Rounding out the intelligent mix of materials is the magnesium strut brace. A comparison with the predecessor model shows that it contributes a 28-percent weight saving.

The carbon rear panel in the new Audi A8
In terms of its overall dimensions, an ultra-high-strength, torsionally rigid rear panel made of CFRP is the largest component in the occupant cell of the new Audi A8, and it contributes 33 percent to the torsional rigidity of the total vehicle. To optimally absorb longitudinal and transverse loads as well as shearing forces, between 6 and 19 fiber layers are placed one on top of another, ensuring a load-optimized layout. These individual fiber layers consist of tapes 50 millimeters (0.2 in) wide and can be placed individually in a finished layered panel, with any desired fiber angle and minimal trimming of the fibers. The innovative direct fiber layering process specially developed for this purpose makes it possible to entirely dispense with the normally required intermediary step of manufacturing entire sheets of carbon fiber. Using another newly developed process, the layered panel is wetted with epoxy resin and cured within minutes.

Laser remote welding of aluminum
High precision work naturally demands new production processes to be adopted. With remote laser welding of aluminum, Audi has developed a new approach and in so doing has gained Vorsprung over other premium automakers. Exact positioning of the laser beam in relation to the welding edge considerably reduces the risk of hot cracking because the heat input can be precisely controlled. The size of the gap between parts being joined can immediately be determined and effectively filled in by means of process control strategies. The laser beam’s high feed rate and low energy use reduce CO₂ emissions by about one quarter. This new process also results in a 95-percent saving on recurring costs in series production because it eliminates the need for the costly process controls required with conventional laser welding.

Ultra lightweight construction in the R8 Spyder
Also seeking to use the best material in the best place is the new R8 Spyder (combined fuel consumption in l/100 km: 12.5 – 11.7* (18.8 – 20.1 US mpg); combined CO₂ emissions in g/km: 292 – 277* (469.9 – 445.8 g/mi)). Here, the benefits are threefold: the sports car is lighter, stiffer and faster than its predecessor. Contributing significantly to this is the intelligent mix of materials, which has, of course, been precisely tailored to the peak performance levels of a driving machine which aspires to be an elite athlete.

To this end, the Audi Space Frame has a new multi-material structure with structurally integrated carbon. The entire ASF consequently weighs just 208 kilograms (458.6 lb), with the vehicle as a whole coming in 15 percent lighter than previously (a reduction of around 25 kg (55.1 lb)). Despite this, the engineers have succeeded in increasing the rigidity of the frame by 50 percent. A class-beating achievement. And it shouldn’t be forgotten that this consistent lightweight construction has once more improved driving performance. An output of 540 hp delivers a top speed of 318 km/h (197.6 mph), whilst the 0 to 100 km/h (0 to 62.1 mph) sprint takes just 3.6 seconds. Or put another way: Vorsprung durch lightweight construction.

2. Audi g-tron models with Audi e-gas: the energy revolution in the tank

In addition to TFSI and TDI engines, Audi is increasingly banking on alternative drive systems. One focal point here is the g-tron models. They operate on compressed natural gas (CNG) and enable virtually CO₂-neutral mobility thanks to the synthesized Audi e-gas.

Sporty, efficient and highly cost-effective: the Audi g-tron models
Audi launched its first natural gas-powered model in 2014 – the A3 Sportback g-tron (CNG consumption in kg/100 km: 3.6 – 3.3*; combined fuel consumption in l/100 km: 5.5 – 5.1* (42.8 – 46.1 US mpg); combined CO₂ emissions in g/km (CNG): 98 – 89* (157.7 – 143.2 g/mi); combined CO₂ emissions in g/km (gasoline): 128 – 117* (206.0 – 188.3 g/mi)). The compact five-door model features a 1.4 TFSI with an output of 81 kW (110 hp) and 200 Nm (147.5 lb-ft) of torque between 1,500 and 3,500 rpm. The compact engine sets standards with respect to efficiency and fuel economy. When equipped with the optional S tronic, the bivalent A3 Sportback boasts NEDC (New European Driving Cycle) fuel economy of just 3.3 kilograms CNG per 100 km (5.1 liters (1.3 US gal) gasoline), corresponding to emissions of 89 grams CO₂ per kilometer (143.2 g/mi) and 117 grams CO₂(188.3 g/mi) in gasoline mode. Fuel costs for CNG are less than four euros per 100 kilometers (as of: May 2017).

The two tanks in the A3 Sportback g-tron (CNG consumption in kg/100 km: 3.6 – 3.3*; combined fuel consumption in l/100 km: 5.5 – 5.1* (42.8 – 46.1 US mpg); combined CO₂ emissions in g/km (CNG): 98 – 89* (157.7 – 143.2 g/mi); combined CO₂ emissions in g/km (gasoline): 128 – 117* (206.0 – 188.3 g/mi)) are located under the luggage compartment floor and each store around 7 kilograms (15.4 lb) of gas at a maximum pressure of 200 bar. They reduce luggage space only marginally and are constructed from a composite material, making them very lightweight.

Range with gas in the NEDC is more than 400 kilometers (248.5 mi). The 50-liter (13.2 US gal) fuel tank adds an additional 900 kilometers (559.2 mi). The car switches from one operating mode to the other automatically without the driver having to intervene. The instrument cluster separately displays the residual ranges in both modes.

In late summer 2017, the A4 Avant g-tron (CNG consumption in kg/100 km:
4.4 – 3.8*; combined fuel consumption in l/100 km: 6.5 – 5.5* (36.2 – 42.8 US mpg); combined CO₂ emissions in g/km (CNG): 117 – 102* (188.3 –  164.2 g/mi); combined CO₂ emissions in g/km (gasoline): 147 – 126* (236.6 – 202.8 g/mi)) and the A5 Sportback g-tron (CNG consumption in kg/100 km: 4.3 – 3.8*; combined fuel consumption in l/100 km: 6.4 – 5.6* (36,8 – 42.0 US mpg); combined CO₂ emissions in g/km (CNG): 115 – 102* (185.1 – 164.2 g/mi); combined CO₂ emissions in g/km (gasoline): 144 – 126* (231.7 – 202.8 g/mi)) will extend the natural gas lineup. Both models are driven by a 2.0 TFSI engine with the highly efficient “B cycle” combustion process developed by Audi.

The pistons and valves have been specially modified for gas operation and allow for an optimal compression ratio. The turbo engine adapted for CNG operation produces 125 kW (170 hp). Its maximum torque of 270 Newton meters (199.1 lb-ft) is available at 1,650 rpm. An electronic controller reduces the high pressure of the gas flowing from the tank from as much as 200 bar to a working pressure of 5 to 10 bar in the engine. This operation is performed dynamically and precisely in response to the power requested by the driver. The correct pressure is always present in the gas line and at the injector valves – low pressure for efficient driving in the lower speed range, and higher pressure for more power and torque.

Altogether, Audi engineers have achieved unparalleled efficiency in CNG engines through these measures. In the NEDC, the Audi A4 Avant g-tron with optional S tronic consumes just 3.8 kilograms CNG per 100 kilometers, corresponding to CO₂ emissions of 102 grams per kilometer (164.2 g/mi). In gasoline mode, these figures are 5.5 liters per 100 kilometers (42.8 US mpg) and 126 grams of CO₂ per kilometer (202.8 g/mi). The figures for the A5 Sportback g-tron with S tronic are identical in CNG mode. In gasoline mode, it consumes 5.6 liters per 100 kilometers (42.0 US mpg) and emits 126 grams of CO₂ per kilometer (202.8 g/mi). Both models accelerate from 0 to 100 km/h (62.1 mph) in 8.4 seconds. The A4 Avant g-tron reaches a top speed of 221 km/h (137.3 mph), the A5 Sportback g-tron 224 km/h (139.2 mph).

With a tank capacity (at 15 degrees Celsius) of 19 kilograms, both g-tron models have a range of up to 500 kilometers (310.7 mi). When the pressure in the tank falls to less than 10 bar with about 0.6 kilograms remaining, the engine management automatically switches to gasoline operation. The two mid-size models can cover an additional 450 kilometers (279.6 mi) in this mode. The filler necks for gas and gasoline are located together under the tank flap.

Two indicators inform the driver about the fill levels of the tanks. The driver information system shows the fuel consumption in the active operating mode. After refueling, the engine is first started with gasoline in order to analyze the gas quality. The same is true in extremely cold conditions. It then changes as quickly as possible to gas mode. Switching takes only a few tenths of a second and is virtually imperceptible.

The four cylindrical CNG tanks are mounted as a compact module in the rear of the car. They are optimized for the available space, and each is specifically sized. Sheet steel shells with tensioning straps hold the cylinders and protect them against damage, such as curbs. The complete CNG tank module, which also includes the 25 liter (6.6 US gal) gasoline tank, is installed during production of the g-tron models. The spare wheel well has been eliminated. The battery has also moved from the luggage compartment to the engine compartment. The loading floor is level with the loading lip, thus offering a full-fledged luggage compartment.

The CNG tanks follow the Audi lightweight construction philosophy. Thanks to their innovative layout, they weigh 56 percent less than comparable steel cylinders. Their inner layer is a gas-tight matrix of polyamide. The second layer, a composite winding of carbon-fiber-reinforced polymer (CFRP) and glass-fiber-reinforced polymer (GFRP), provides maximum strength. The third layer is pure GFRP and serves primarily as a visual inspection aid, turning milky white where damaged. Audi experts test each tank at 300 bar during production before it is installed in a car. The actual bursting pressure is much higher still and far exceeds the legal requirements.

Virtually carbon-neutral driving: Audi e-gas
Compared with gasoline, combustion of natural gas emits 25 percent less CO₂ due to the lowest carbon content of all hydrocarbons. In addition, particulate emissions remain very low. For an even better energy balance, Audi produces sustainable Audi e-gas, which is virtually identical chemically to high-quality natural gas. When operating with this synthetic gas, the g-tron-fleet is virtually carbon-neutral according to the well-to-wheel analysis (from fuel source to the wheel). The CO₂ balance sheet is lower by 80 percent relative to a comparable gasoline model**.

The fuel is produced from water and carbon dioxide with green electricity or from recyclable materials, such as straw and green waste. Production is petroleum-independent and does not compete with food production. With Audi e-gas, a g-tron model emits only as much CO₂ from its exhaust pipes as was bound during production of the fuel.

Audi offers this fuel for three years as a standard feature to customers ordering a g-tron model by May 31, 2018. Customers can fill up their g-tron model at any CNG filling station and pay the regular price. By feeding the volume of Audi e-gas consumed according to the NEDC into the European natural gas grid, Audi ensures the green benefits of the program, including the corresponding reduction in CO₂ emissions. This occurs automatically on the basis of surveys and service data from the cars. TÜV Süd, a German testing and certification authority, monitors and certifies the process. Audi g-tron customers receive a document that confirms their car will be supplied with Audi e-gas and informs them about the certification.

Audi obtains the e-gas from its own power-to-gas facility in Werlte in Lower Saxony (Emsland), among other places. In operation since 2013, the plant produces up to 1,000 tons of e-gas per year. Absorbing up to 2,800 tons of CO₂ in the process. This quantity enables around 1,500 Audi g-tron models to drive 15,000 kilometers (9,320.6 mi) each year virtually CO₂-neutrally.

The Audi e-gas plant produces the renewable fuel in two steps – electrolysis and methanation. In the first step, the plant uses renewably generated electricity to split water into oxygen and hydrogen. In the medium term, the latter can also serve as a fuel for fuel cell cars. The absence of any universal hydrogen infrastructure at present means that the focus today lies on the second process step: the hydrogen reacts with CO₂ from the exhaust stream of an adjacent waste-fed biogas plant. The result is synthetic methane – Audi e-gas.

Potential: expansion of the CNG grid and new production methods
The Audi e-gas plant in Werlte demonstrates just how well the power-to-gas concept – the conversion of electricity into fuel – works. Power-to-gas plants allow storage of surplus renewable energy, thereby making a valuable contribution to the energy transition. At the same time, the Audi e-gas plant helps stabilize the power grid at high feed-in rates of renewable energy. This makes Audi technology both a part and a driver of the energy revolution.

In view of the growing g-tron fleet, Audi is expanding its e-gas capacities through new cooperative arrangements. Our partners are the Thüga Group and Viessmann GmbH. The latter is working on a biological rather than chemical methanation process. Audi also obtains methane from certified residual material biogas plants that meet strict sustainability criteria.

In early 2017, the Volkswagen Group, filling station operators and gas networks committed to expanding CNG mobility in a joint memorandum of understanding. The goal is, together with other automakers, to expand the CNG fleet in Germany tenfold to one million units by 2025. At the same time, the filling station network in the Germany is to be expanded from currently 900 to 2,000 locations by 2025. In other European countries, too, the consortium intends to press ahead with the expansion in compliance with the requirements of EU Directive 2014/94 (deployment of alternative fuels infrastructure).

Besides the e-gas project, Audi is conducting research on other sustainable fuels: the Audi e-fuels. Audi e-diesel, Audi “e-benzin” (e-gasoline) and Audi e-ethanol are also synthetic fuels of the latest generation. In the case of all these fuels, their production absorbs the quantity of CO₂ emitted by the car during operation – the carbon dioxide is recycled. The driving force in the production of e-fuels is renewable energy.

3. Environmentally friendly, sporty, practical – electric mobility at Audi
The car of the future is emission-free and does not burn fossil fuels. It is sporty, efficient and suitable for everyday use. Audi has taken an important step toward purely electric mobility with its plug-in hybrids. The Audi A3 Sportback e-tron (combined fuel consumption in l/100 km: 1.8 – 1.6* (130.7 – 147.0 US mpg); combined energy consumption in kWh/100 km: 12.0 – 11.4*; combined CO₂ emissions in g/km: 40 – 36* g/km (64.4 – 57.9 g/mi)) and the Audi Q7 e-tron 3.0 TDI quattro (combined fuel consumption in l/100 km: 1.9 – 1.8* (123.8 – 130.7 US mpg); combined energy consumption in kWh/100 km: 19.0 – 18.1*; combined CO₂ emissions in g/km: 50 – 48* g/km (80.5 – 77.2 g/mi)) combine the electric drive with efficient combustion engines. Thanks to the development of battery cells with a higher energy density and thus greater range, Audi will achieve the next milestone in 2018: all-electric driving in volume production models.

The sporty Audi e-tron SUV (This vehicle is not yet available on the market. It does not yet have type approval and is therefore not subject to Directive 1999/94/EC.) will kick things off. It offers the space and comfort of a typical Audi full-size vehicle and a range of over 500 kilometers (310.7 mi). This will be followed in 2019 by a four-door Gran Turismo – the production version of the Audi e-tron Sportback concept, which the premium manufacturer presented at Auto Shanghai 2017. Audi will expand its electric range to include a compact model one year after that. In 2020, customers will therefore be able to choose from three all-electric vehicles from the brand with the four rings. From 2021, all core model series are to be electrified, including mild-hybrid technology. Taking planned volume growth into consideration, one-third of all Audi models will drive exclusively on electricity in 2025. Two-thirds will be partly electrified combustion engine vehicles.

From combustion engine to electric drive: plug-in hybrid as bridge technology
Audi has been developing models with all-electric or hybrid drive since the late 1980s. The first production offering of a car combining a combustion engine with an electric motor was the Audi duo from 1997, which occupied the body of an Audi A4 Avant. A landmark technological development for electric cars was the Audi R8 e-tron, which was unveiled at the 2009 Frankfurt Motor Show and in 2012 set a record lap time for an electric car on the Nordschleife of the Nürburgring.

Since 2014 Audi has offered the 150 kW (204 hp) A3 Sportback e-tron (combined fuel consumption in l/100 km: 1.8 – 1.6* (130.7 – 147.0 US mpg); combined energy consumption in kWh/100 km: 12.0 – 11.4*; combined CO₂ emissions in g/km: 40 – 36* (64.4 – 57.9 g/mi)), which is both the first Audi plug-in hybrid as well as the first PHEV (plug-in electric vehicle) in the premium compact segment. A 1.4 TFSI is paired with a powerful electric motor for a system output of 150 kW (204 hp). A separating clutch controls the interplay between engine, motor and six-speed S tronic. The lithium-ion battery can be recharged via recuperation and using a cable. It provides 8.8 kWh of energy, enough for an all-electric range of up to 50 kilometers (31.1 mi).

2016 saw the debut of the Audi Q7 e-tron (combined fuel consumption in l/100 km: 1.9 – 1.8* (123.8 – 130.7 US mpg); combined energy consumption in kWh/100 km: 19.0 – 18.1*; combined CO₂ emissions in g/km: 50 – 48* (80.5 – 77.2 g/mi)). Powered by the combination of a 3.0 TDI engine and an electric motor, system output is 275 kW (373 hp) and 700 Nm (516.3 lb-ft) of torque. It accelerates from a standing start to 100 km/h (62.1 mph) in 6.2 seconds and is particularly efficient. Its battery has a capacity of 17.3 kWh. The Q7 e-tron thus has an all-electric range of up to 56 kilometers (34.8 mi) while producing zero local emissions. It is the world’s first plug-in hybrid with a V6 diesel engine and quattro drive. Like the A3 Sportback e-tron, the luxury SUV consumes on average less than two liters of fuel per 100 kilometers (117.6 US mpg). It uses a highly efficient heat pump for the thermal management of the drive and the interior.

The Audi A8 L e-tron quattro (This vehicle is not yet available on the market. It does not yet have type approval and is therefore not subject to Directive 1999/94/EC.) sees a plug-in hybrid model joining the new A8 model series line-up next year. Its 3.0 TFSI and the electric motor, which is integrated into the eight-speed tiptronic together with the separating clutch, generates 330 kW (449 hp) of system power and 700 Nm (516.3 lb-ft) of system torque. The lithium-ion battery stores 14.1 kWh of energy. The big sedan can cover roughly 50 kilometers (31.1 mi) solely on electric power.

From 2018: all-electric driving in volume models
Audi is launching its first all-electric production model next year. The brand presented its precursor, the Audi e-tron quattro concept, at the IAA 2015. As an SUV with a completely new design, the new Audi e-tron (This vehicle is not yet available on the market. It does not yet have type approval and is therefore not subject to Directive 1999/94/EC.) delivers a range of more than 500 kilometers (310.7 mi) despite offering the space and comfort levels of a typical full-size Audi model. This gives customers the freedom to continue driving in the future without having to change their habits.

The concept car is equipped with three electric motors producing a peak output of 370 kW and more than 800 Nm (590.0 lb-ft) of torque. The flexible management system enables electric quattro drive and electric torque distribution for high dynamics and stability. The large lithium-ion battery stores 95 kWh of energy and is mounted at the ideal center of gravity below the occupant cell. The Audi e-tron quattro concept sprints from 0 to 100 km/h (62.1 mph) in just 4.6 seconds. This is on the level of a high-performance sports car.

The production model of the electric-powered SUV will be produced at the Brussels site, where Audi is also building its own battery production facility. The Audi e-tron marks the dawn of a new era for the manufacturer. In 2020 the manufacturer will have three all-electric vehicles in its range, with a four-door Gran Turismo – the production version of the Audi e-tron Sportback concept – and a model in the compact segment joining the sporty SUV.

Convenient charging solutions: for home and on the move
Convenient and rapid charging is essential for the success of electric mobility. In 2018, Audi will already be equipping the A8 L e-tron quattro and the Audi e-tron (Both vehicles are not yet available on the market. They do not yet have type approval and are therefore not subject to Directive 1999/94/EC.) with a new technology as standard: Audi Wireless Charging (AWC) which enables inductive charging using alternating current. An inductive charging station with integral coil is placed on the floor where the car is to be parked, and connected to the power supply. Once the driver positions his/her e-tron model over the plate with the help of the MMI display, charging with roughly 3.6 kW begins automatically.

The alternating magnetic field induces an alternating voltage in the secondary coil fitted in the floor of the car, across the air gap. The integrated electronics convert the alternating current to direct current and feed it into the high-voltage electrical system. AWC technology is ideal for the garage or office parking lot. It is also suitable for outdoor use and can be bolted into the ground to prevent theft.

Alternatively, customers can charge their car’s battery at home via cable, for which Audi offers a convenient wall-mounted holder. A 7.2 kW industrial outlet can fully charge the A8 L e-tron quattro in roughly two hours. The all-electric Audi e-tron, whose charging cable supports a power of 11 kW, can be fully charged overnight. Total range on a fully charged battery is more than 500 kilometers (310.7 mi). The driver starts the charging process conveniently from the MMI system. Charging can also be started remotely using the driver’s smartphone and the my Audi Remote app, which also allows the programming of charging timers.

Whilst on the move, the drivers of all-electric cars can charge their vehicles using direct current – the higher the power, the faster the charging. Together with the BMW Group, Daimler AG and the Ford Motor Company, the Volkswagen Group with Audi and Porsche wants to establish the highest-performance charging network in Europe. Plans call for 400 stations with multiple chargers to be in installed along highways and freeways by 2020. Each charger will deliver up to 350 kW of power to provide true suitability for long-distance mobility. 

Racing as a development lab: Audi in the Formula E
Racing is the toughest development lab and test bed for series production, and electricity is powering Audi’s race for the future through the company’s involvement in Formula E. In the current season, the motorsports division assists the ABT Schaeffler Audi Sport team. Audi is planning to enter a full factory team for the 2017/2018 season in order to gather additional experience with batteries, electric motors and power electronics under extreme conditions.

4. CO₂-neutral plant in Brussels: clean cars from a clean factory
More and more people are making their consumer choices based on sustainability. Audi has taken this core strategic concept of the premium brand one critical step further: the company takes a holistic approach to its product range. Anyone wishing to achieve genuine Vorsprung where sustainability is concerned needs to consider not just the product itself and its environmental footprint, but must instead start much earlier in the process. The Brussels plant is playing a pioneering role in this regard.

The Brussels plant is where the first electric car of the Audi brand is being manufactured. A car such as this calls for sustainable value creation. Audi therefore plans to make the energy supply for the Audi e-tron plant CO₂-neutral in the coming years. As at all other plants, a task such as this starts with a stock-taking exercise. Audi knows its own CO₂ footprint very precisely and has it certified independently. It is anticipated that the Brussels plant, for example, will emit around 30,000 tonnes of CO₂ in 2018. 97 percent of those emissions will originate from burning natural gas for heating, while the rest will come from the fuel consumption of company vehicles, heating oil and the burning of solvents.

Compared with its industry peers, Brussels is already an exceptionally green site. Audi gets all its electricity for the plant from renewable sources. There is also an on-going program of new energy management measures. These include, for example, a heat pump in the paint pre-treatment area, a cogeneration system for electricity and energy-saving LED lighting in all production halls. The next stage is the procurement of green gas in order to reduce emissions. As a result, the site will be CO₂-neutral from January 2018; this applies to both Scope 1 and Scope 2 emissions, as defined in the official Greenhouse Gas Protocol.

Any remaining emissions will be balanced out by compensation projects at other locations. The CO₂ footprint of the Brussels plant will therefore be practically invisible, and this, of course, has been confirmed by independent certifying bodies. Or to put it simply: clean cars from a clean factory. That’s Vorsprung.

5. Key technology for the future: the fuel cell
Hydrogen as an energy source is the next big step on Audi’s electrification roadmap. With weight advantages and attractive system costs, the fuel cell is an alternative to high-voltage batteries, particularly for larger electric vehicles. Models with this technology have a long range and can be refueled in just a few minutes. Customers therefore don’t have to make any adjustments when switching from a combustion engine to a fuel cell.

Audi has the leading role at the Volkswagen Group for the development of this technology. The Neckarsulm site is the competence center for hydrogen and fuel cell research, one of the key technologies in the development of future drive systems. The brand with the four rings is currently expanding the site to include production and pre-production development.

The course has also been set with respect to infrastructure: filling station operators, vehicle manufacturers and the public sector have joined forces to establish a broad network of national and international funding programs to ensure the efficient use of resources. According to this group, the infrastructure required for large-scale series production in international markets will also be in place in 2025. Plans call for roughly 1,000 hydrogen filling stations in Germany by 2030 – enough for sufficient country-wide coverage.

Trendsetting: concept cars and technology demonstrators
Audi has been working on fuel cell concepts for more than ten years now. The first test vehicle, the compact A2H₂, was produced in 2004. It had a 110 kW electric motor, and a nickel-metal hydride battery served as a buffer. The Audi Q5 HFC (Hybrid Fuel Cell) followed in 2009. Its fuel cell had an output of 90 kW and was supported by a compact lithium-ion battery. Later Audi models with fuel cell technology bear the moniker “h-tron,” with the “h” standing for the element hydrogen. The company is using these vehicles to demonstrate its mastery of fuel cell technology – precisely as one would expect from the brand: sporty, emotional, efficient and clean.

A7 Sportback h-tron quattro
Audi presented the A7 Sportback h-tron quattro at the 2014 Los Angeles Auto Show. International automotive journalists were able to experience the technology demonstrator for themselves on public roads. 

It uses a powerful, sporty electric drive system with a fuel cell as the energy source combined with a hybrid battery and an additional electric motor at the rear of the car. Its drive configuration makes the emission-free Audi A7 Sportback h-tron quattro a quattro through and through, with 170 kilowatts of power at its disposal. There is no mechanical connection between the front and rear axles. As an e-quattro, the big coupe features fully electronic management of torque distribution. With 540 Nm (398.3 lb-ft) of torque, it sprints from 0 to 100 km/h (62.1 mph) in 7.9 seconds on its way to top speed 180 km/h (111.8 mph). In 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) – an amount containing as much energy as 3.7 liters (1.0 US gal) of gasoline.

The four hydrogen tanks of the A7 Sportback h-tron quattro are located beneath the floor of the trunk, in front of the rear axle and 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 (11.0 lb) of hydrogen at a pressure of 700 bar – sufficient for a range of over 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 thus has crucial extra range in reserve.

Audi h-tron quattro concept
The basic concept of the A7 Sportback h-tron quattro is similar to that of the Audi h-tron quattro concept. Audi presented this model at the 2016 North American International Auto Show in Detroit. Its fuel cell, or stack, is located in the front of the car. Comprising 330 individual cells, it has a peak output of 110 kW. With an efficiency rating in excess of 60 percent, it easily surpasses any combustion engine. At a pressure of 700 bar, the three tanks store enough hydrogen for a range of up to 600 kilometers (372.8 mi). It takes only around four minutes to completely refuel.

Mounted under the vehicle floor is a compact lithium-ion battery weighing less than 60 kilograms (132.3 lb). It provides as much as 100 kW of additional power when accelerating and stores energy when braking. With 550 Nm (405.7 lb-ft) of system torque, the Audi h-tron quattro concept sprints from zero to 100 km/h (62.1 mph) in less than seven seconds. Top speed is governed at 200 km/h (124.3 mph).

The power from the fuel cell and the high-voltage battery drives two electric motors – the first is located on the front axle and delivers an output of 90 kW, while the other is positioned at the rear axle and supplies 140 kW. This concept makes the technology study an electrified quattro. An intelligent management system controls the interplay between them as appropriate for the situation, placing maximum emphasis on efficiency. A heat pump for the interior air conditioning and a large solar roof that generates up to 320 watts, equivalent to adding up to 1,000 kilometers (621.4 mi) to the range annually, also boost efficiency.

In the NEDC, the concept car uses around one kilogram of hydrogen per 100 kilometers (2.2 lb per 62.1 mi), corresponding to the energy contained in 3.7 liters (1.0 US gal) of gasoline.

Hydrogen from Audi: global emission-free driving
The two h-tron technology demonstrators from Audi can drive emission-free not just locally, but also globally. This pre-supposes that the hydrogen in the tanks is produced using green, i.e. renewably generated electricity, such as is the case at the Audi e-gas plant in Emsland. The world’s first industrial power-to-gas plant in Werlte, Lower Saxony, began operation in 2013. It uses electricity generated with wind power to produce hydrogen via electrolysis. This process breaks down water into oxygen and hydrogen. The hydrogen is currently used in a second process step to produce Audi e-gas, a synthetic methane for the Audi g-tron models. In the future, however, the hydrogen can be used directly as fuel for fuel cell vehicles. Audi will launch the first production h-tron in the first half of the next decade.

6. CO₂ capturing: clear air bubbling with added value
Sustainability is only a token gesture if it’s not thought through to the end. Vorsprung means looking at the entire chain “from well to wheel”. Audi sets the benchmark in this regard. And at the Barcelona Summit, visitors can even taste the results. A new technology captures CO₂ from the air. The carbon dioxide collected in this way can be used to turn fresh water into sparkling water. A closed-cycle process that benefits the environment.

Audi has developed the technology together with Swiss start-up company Climeworks. Using a new type of filter material, the climate-harming gas can be chemically bound to the filter’s surface. Once the filter is sufficiently saturated, the CO₂ is released back out of the filter by heating it to 90 degrees C. The CO₂ can then be re-used to benefit the environment. Under Audi’s mentoring, a cooperative venture has been set-up between Climeworks and a partner of the beverage industry to add CO₂ captured directly on site to the drinks manufacturer’s bottles. As a result, the CO₂ no longer has to be delivered in cylinders, thereby cutting the number of transport movements considerably. A double bonus for the environment.

For Audi, CO₂ capturing has even greater long-term prospects: CO₂ and water, combined with renewable energy, can be used to manufacture synthetic fuels such as gasoline and diesel. This process can also be used to convert renewable energies into liquid fuels and store them. Together with partners sunfire and Climeworks, the brand with the four rings is already operating a pilot plant near Dresden which is manufacturing synthetic diesel from carbon dioxide, water and renewable electricity. At an efficiency of between 65 and 70 percent, around 160 liters (42.3 US gal) of Blue Crude can be manufactured per day. Nearly 80 percent of that can be converted into synthetic diesel. Audi e-diesel is free of sulfur and aromatics. It also has a high cetane number, which means that it ignites very easily.

7. Audi Environmental Foundation:  pushing the boundaries with greenovations
More. This small word is often used to define what Vorsprung is all about. It means delivering more than what the customer, employee, society or the environment expects. An example of this is the not-for-profit Audi Environmental Foundation. AUDI AG founded it in order to commit itself on a voluntary basis to more than just the legally stipulated regulations, and to look at combining environment and technology with one another. In Barcelona, the Foundation will be showing its origins and its aims. It also benefits from the unique innovative potential of the premium brand. Engineering concepts have evolved into genuine greenovations which are helping us to comprehend and protect the very basis of our existence.

7.1 Smart HOBOS – the high-tech beehive
The Smart HOBOS high-tech beehive at Audi’s production site in Münchsmünster is a research station run jointly with the University of Würzburg. Cutting-edge technologies provide novel insights into the honey bee superorganism to anyone anywhere in the world, 24 hours a day.

Enthusiasts and scientists can observe the 20,000 honey bees in the hive via live stream at www.hobos.de (HOneyBee Online Studies). A 360-degree pivoting robot arm has also been installed inside the hive. This is fitted with an infrared and thermal imaging camera and a 3D sensor to record activities in and around the hive 24 hours a day. Thermographic images provide new perspectives of individual bees and the whole colony without disturbing the insects. The latest technology is also being used to document the effects of external factors such as air humidity, temperature and light incidence, providing a valuable insight into bee behavior.

7.2 The megacities experiment
The Audi Environmental Foundation has already planted more than 100,000 trees. There’s a scientific background to this green initiative which is enormously important, both for the environment and society, particularly in the light of increasing urbanization. An international research project is studying the plantations to examine the interaction between stocking density on the one hand and CO₂ absorption potential and biological diversity on the other.

The objective is to establish how best to plant trees in order to achieve the greatest possible absorption of carbon and the best conditions for wide-ranging biodiversity. The oak is among the most suitable tree species because, as mature trees, they store a large quantity of carbon and also provide good conditions for biodiversity. Oaks are also especially robust when it comes to the changing demands of the future climate.

To this end, in megacities in different climate regions around the world, trees along measuring routes extending from the city center to the outskirts are being analyzed for their growth. Megacities were chosen because it is here where the urban climate effect is most obvious, and differences between the heavily built-up city center and the less densely developed peripheries are most pronounced. It also makes it possible to compare tree growth at test sites with different climates. The relationship between environmental conditions and tree growth will help to reveal how tree growth is likely to respond to climate change. Growth ring analyses, structural analyses, state-of-the-art scanning techniques and isotope analyses are used in the investigation.

The results of the project will be hugely relevant for both science and future practice. They will contribute significantly to research into climate change and forest growth and will help to develop suitable adaptation strategies for forests in the changing climatic conditions. Vorsprung for the environment, so to speak.

The project is unique in terms of the trees being investigated and variety of project sites. As the sites are spread throughout the world, it has been possible not only to discover more about tree growth in urban areas in different climate zones but also to analyze different growth conditions and factors influencing tree growth.

The project is being run by the Institute for Forest Growth Research at the Technical University of Munich.

The equipment, data and prices specified in this document refer to the model range offered in Germany. Subject to change without notice; errors and omissions excepted.