Sustainability and new drive technologies
Audi has placed electric drive technologies at the center of development – covering a wide range of applications. The matrix ranges from smart electrical systems to all-electric cars which are locally and globally emission-free. At the same time, the company is working on synthetic fuels that do not depend on petroleum; these fuels also pave the way for new sustainable mobility.
In addition, Audi prepares a life cycle assessment for every new model in order to determine the environmental footprint of its products – always with the goal of further decreasing their impact on the environment. The assessment considers all phases of the vehicle life cycle – production of the materials and components, manufacturing of the vehicle itself, recycling, and the key factor of the utilization phase.
Audi has entered the age of electric mobility. The Company offers or is developing the best form of electrification for every vehicle and drive concept, from mild hybrid to the all-electric car. The range will continue to grow rapidly over the next few years. In motorsport, too, Audi is going electric in the race for the future – in Formula E.
The expertise that Audi possesses in electric mobility goes back a long way – the Company unveiled its first plug-in hybrid model back in 1989. It now has two such cars in the sales program: the A3 Sportback e-tron and the Q7 e-tron 3.0 TDI quattro (in Asia: Q7 e-tron 2.0 TFSI quattro).
In 2018 a sport SUV with all-electric drive will follow – its precursor, the Audi e-tron quattro concept that appeared at the 2015 Frankfurt Motor Show, already anticipated it. The three electric motors have an output of up to 370 kW, and their highly flexible management permits electric quattro drive and electric torque vectoring for impressive dynamics and stability. The 95 kWh battery, located low between the axles, makes a range of over 500 kilometers possible.
The SUV is being built at the Brussels plant, where Audi is setting up its own battery production line. It is a milestone on the road to the future. “From 2018 we will be unveiling a fresh electrified model every year,” declared Rupert Stadler, Chairman of the Board of Management of AUDI AG. “We will have three electric cars on offer by 2020, and by 2025 one-third of our model range will be battery-powered.”
Audi is pressing ahead swiftly with electrification among the new high-voltage electric cars as well. The existing 12-volt electrical system and especially the new 48-volt electrical subsystem offer ample scope for making driving even more comfortable and efficient. New mild hybrids with belt alternator starters will soon take their place in the Audi model range. They will be joined by technologies that enhance driving pleasure. The electric powered compressor (EPC) that supports the engine’s turbocharger and electromechanical active roll stabilization are already in volume production. Electromechanical active roll stabilization opens up new horizons for handling and also offers recuperation, with kinetic energy converted into electrical energy.
Audi both drives competition and is driven by a competitive instinct – from now on, the Company will be competing in Formula E. The electric racing cars of the ABT Schaeffler Audi Sport team will be competing for the Four Rings in the current season, and for 2017/18 Audi, is planning full-scale manufacturer commitment. In motorsport, too, as the toughest testing environment for production, Audi is going electric in the race for the future.
At Audi the abbreviation e-tron stands for automobiles that can cover long distances in electric mode and can recharge electricity from a power socket. Audi now has two e-tron models in its lineup: the A3 Sportback e-tron and the Q7 e-tron 3.0 TDI quattro. Both combine an electric drive with efficient combustion engines. This plug-in technology represents an important step on the way to electric mobility.
The compact Audi A3 Sportback e-tron pairs a 1.4 TFSI gasoline engine, which outputs 110 kW (150 hp) and 250 Nm of torque, with an electric motor that produces 75 kW and 330 Nm. The system power of 150 kW (204 hp) enables very agile driving performance. The flat lithium-ion battery providing 8.8 of kWh of energy is mounted under the rear bench. A decoupler controls the interplay between the combustion engine, electric motor and six-speed S tronic.
The drivetrain strategy of the Audi A3 Sportback e-tron can manage both powerplants so they work extremely efficiently. If the driver takes their foot off the accelerator, energy is recovered by means of recuperation or the vehicle coasts with the drivetrain disconnected – depending on the driving situation. At speeds up to 130 km/h, the vehicle can be driven in all-electric mode, with an electric range of 50 km and zero exhaust emissions in the standard test cycle.
The Audi Q7 e-tron 3.0 TDI quattro adopts the same technology principle, but simply ramps it up a notch. It produces 285 kW (373 PS) of system output and 700 Nm of system torque; its battery has a capacity of 17.3 kWh. Just like the A3 Sportback e-tron, the large SUV consumes on average less than two liters of fuel per 100 km, according to the relevant standard for plug-in hybrid vehicles in which the electric motor and combustion engine share the load in the test cycle. It uses a heat pump for the thermal management of the drive and the air conditioning in the interior; this pump is far more efficient than conventional systems. In Asia, Audi offers the Q7 e-tron 2.0 TFSI quattro with a gasoline engine instead of the diesel hybrid.
The Audi connect e-tron services and the Audi MMI connect app enable Audi customers to remotely check the status of their car, such as the battery charge level and electric range, various types of service information and the car’s location. The driver can also remotely control the charging schedule and the stationary climate control.
Electric motoring is the future of mobility – Audi is convinced of that. But the technology will only take off if the charging process is convenient. Electromobility will become a compelling, sustainable option only if the electricity is generated from sustainable sources. The system portfolio Audi is developing allows customers to charge their vehicles using renewable energy from the private and public infrastructure.
Audi and Volkswagen customers can charge and fuel in Germany with the “Charge&Fuel Card”. Charging your electric vehicle will become much easier with the Charge&Fuel App and Card: You receive one single, monthly invoice no matter which of our publicly accessible charging stations of Charge&Fuel cooperation partners in Germany you are using. Moreover, you are able to make cashless payments for fuel or other services (e.g. car wash) at more than 10.800 petrol stations of the UTA network. For further information please visit www.chargeandfuel.de.
Inductive charging using alternating current is the next stage for the Audi e-tron models. Here a floor-mounted charging plate transfers the energy to a receiver coil in the car, inverts it and feeds it into the high-voltage electrical system. The technology is ideal for domestic garages or office parking garages; a subsequent expansion stage could see the technology also integrated into the asphalt on roads and parking lots.
All-electric cars can also be charged on the move using direct current – the higher the charging output, the faster the process. The Volkswagen Group with Porsche and Audi now intends to set up Europe’s most powerful charging network in conjunction with the BMW Group, Daimler AG and the Ford Motor Company. Through 2020, several thousand stations will be located on highways and transit routes, providing up to 350 kW of power. This will enable even an all-electric vehicle with a large battery to be recharged in a few minutes. The Combined Charging System (CCS) will provide the requisite plug technology.
Over the medium term, AUDI AG also aims to turn electrified vehicles into smart grid elements. This grid networks and controls electricity producers, electricity storage devices and electric consumers intelligently and efficiently.
Virtually climate-neutral driving – it is already possible today with Audi e-gas, one of the new e fuels from Audi. Using green power, Audi e-gas is produced from water, carbon dioxide and waste materials. It is not dependent on mineral oil, only as much CO₂ is expelled via the exhaust pipe as was captured during its production process, and it is not in competition with the food production sector.
The Audi e‑gas facility in Werlte (Emsland) has been producing renewable fuel since it was commissioned in 2013. The process involves two major steps culminating in the product synthetic methane – Audi e‑gas. It is chemically identical to fossil-based natural gas, can in effect be distributed throughout Germany over the natural gas grid to CNG filling stations and can then be used to refuel Audi g-tron models.
The Audi A3 Sportback g-tron, which appeared on the market at the start of 2014, is being joined by the new models A4 Avant g-tron and A5 Sportback g-tron at the start of 2017. They are outfitted with a 2.0 TFSI engine that develops 125 kW (170 hp) but uses less than 4.0 kilograms of gas per 100 km in the NEDC. In the gas mode, the range is up to 500 km.
When running on Audi e-gas, the CO2 emissions compared with an equivalent petrol model are cut by over 80 percent* – and that is in the broader well-to-wheel view, which takes account of the production process for the fuel as well as the vehicle’s utilisation phase. This results in a saving of 2,100 kg CO₂ when driven in gas mode (with a mileage of 20,000 km per year) compared to an Audi A3 Sportback 1.4 TFSI, 2,200 kg CO₂ compared to an Audi A4 Avant 2.0 TFSI ultra and 2,400 kg CO₂ compared to an Audi A5 Sportback 2.0 TFSI.
Every year the Audi e‑gas facility in Werlte produces up to 1,000 tonnes of e‑gas, capturing up to 2,800 tonnes of CO2 in the process. That quantity is sufficient for around 1,500 Audi g-tron models to cover an annual 15,000 kilometres each, with virtually no CO2 impact. Audi feeds an amount of gas equivalent to that bought by customers back into the grid in the form of e‑gas. In spring 2017 this green option will be launched as a standard three-year arrangement for owners of new Audi g-tron models in all markets. The familiar Audi e-gas tank card will still be available on request.
To reflect the growth of the g-tron fleet, Audi continues to expand its e-gas capacities through partnerships. Its partners are the Thüga Group, Viessmann GmbH and the clean-tech company Electrochaea – the latter two are working on a biological instead of chemical methanation process. Audi also sources methane from certified biogas plants which operate on waste materials and have to meet tough sustainability criteria.
The Audi e‑gas facility in Werlte demonstrates the effectiveness of the “power-to-gas” concept – the conversion of power into fuel. Power-to-gas plants make it possible to store surplus renewable energy and therefore make a valuable contribution to the energy revolution. The Audi e‑gas facility also helps to stabilize the grid when high levels of renewables are being fed in. Audi technology is therefore both a component and a driver of the energy revolution.
* E.g. A5 Sportback g-tron compared to A5 Sportback 2.0 TFSI in the gas mode according to NEDC, incl. upstream fuel chain
Fuel consumption figures of the referenced models
Audi 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**;
CO2 emissions in g/km (CNG): 98 – 89**;
CO2 emissions in g/km, combined: 128 – 117**
Audi A4 Avant g-tron:
CNG consumption in kg/100 km: 4.4 – 3.8**;
Combined fuel consumption in l/100 km: 6.5 – 5.4**;
CO2 emissions in g/km, combined (CNG): 117 – 100**;
CO2 emissions in g/km, combined: 147 – 124**
Audi A5 Sportback g-tron:
CNG consumption in kg/100 km: 4.2 – 3.8**;
Combined fuel consumption in l/100 km: 6.3 – 5.4**;
CO2 emissions in g/km, combined (CNG): 114 – 100**;
CO2 emissions in g/km, combined: 143 – 124**
**Fuel consumption and CO2 emission figures given in ranges depend on the tyres/wheels used as well as on engine/gearbox variants.
Audi e-fuels – this term denotes the sustainable fuels that Audi is currently developing. As well as the Audi e-gas project the Company is conducting research into Audi e-diesel, Audi "e-benzin" and Audi e-ethanol, the latest-generation synthetic fuels. All e-fuels follow the same principle: Their production process binds virtually the same amount of CO₂ that is emitted again when running the car – the carbon dioxide is largely recirculated. And the driving force behind the production of e-fuels is renewable energy.
A production plant for Audi e-diesel started pilot operation in Dresden-Reick at the end of 2014. The energy technology company sunfire is Audi’s project partner. The plant operates according to the power to liquid principle and uses green power as its primary energy source; the raw materials are water and carbon dioxide, which is supplied by a biogas plant. The efficiency of the overall process is very high, at around 70 percent.
In the first step, water heated up to form steam is broken down into hydrogen and oxygen by means of high-temperature electrolysis. In two further steps, the hydrogen reacts with the CO2 in synthesis reactors – again under pressure and at high temperature. The product is known as blue crude, which – similarly to crude oil – can be refined to create the end product Audi e-diesel. The fuel is free from sulfur and aromatics; its high cetane number makes it readily ignitable.
Audi is also developing Audi "e-benzin", another fuel of the future that does not depend on petroleum. Global Bioenergies S.A. operates a pilot plant near Reims (France) to produce isobutene. The Fraunhofer Center for Chemical-Biotechnological Processes (CPB) in Leuna (Saxony-Anhalt) converts the gaseous isobutene into liquid iso-octane, a high-quality designer fuel. It contains no sulfur or benzene and therefore burns very cleanly. Global Bioenergies is currently erecting a demonstration plant in Leuna, which went into operation at the start of 2017. Medium-term, the project partners aim to modify the process so that it will run entirely without biomass.
Another project is underway in Hobbs, New Mexico (USA). Audi, together with the U.S. biotechnology company Joule, has been running a research plant here since 2012 that produces high-purity Audi e-ethanol and e-diesel. Special microorganisms use sunlight, carbon dioxide and salt or brackish water to produce liquid fuels by direct means. This optimized photosynthesis ultimately produces ethanol and, in the future, diesel fuel; these substances are secreted by the organisms and can then be separated from the medium. Even today, the specific yields per area of the demonstration plant are eight times higher than for the production of bioethanol from wheat, and three times higher than for sugar-beet based bioethanol. Further increases are expected.
An all-electric automobile that can be refueled in four minutes – the Audi h-tron quattro concept eliminates the still excessive charging time of normal electric vehicles. A fuel cell powers the concept study. It generates electricity from hydrogen – a gas which Audi can manufacture CO₂-neutrally in its own power-to-gas plant using green electricity. As such, the company is making an unusual proposal for the mobility of the future.
The Audi h-tron quattro concept, which made its debut in early 2016, presents the fifth generation of fuel cell technology from Audi and Volkswagen. Lightweight materials reduce the weight and improve performance, responsiveness and service life. With an efficiency rating in excess of 60 percent, the fuel cell now comfortably surpasses any combustion engine.
The fuel-cell stack comprising 330 individual cells is housed in the forward structure of the technology study. It is powered using hydrogen. Three tanks are located under the passenger cell or the trunk and store sufficient gas at a pressure of 700 bar for a range of up to 600 kilometers. As with a car with a combustion engine, the tanks can be fully refueled in around four minutes.
Ideally complementing the fuel cell that develops 110 kW, there is a compact lithium-ion battery. It is housed under the passenger cell and delivers up to 100 kW power, which provides an additional boost while accelerating. Fuel cell and battery combined deliver a system output of 185 kW. The power from the fuel cell and the high-voltage battery drives two electric motors – one located on the front axle, the other on the rear axle. This innovative all-wheel concept makes the technology study an electrified Audi quattro.
In the European NEDC comparison cycle the Audi h-tron quattro concept consumes around one kilogram of hydrogen per 100 kilometers. It is not only locally, but also globally almost emission-free – provided the gas in the tank is produced using green electricity, as the company does in the Audi e‑gas plant in Lower Saxony.
AUDI AG is responsible for the development of fuel cells within the Volkswagen Group; the Group branch office is based at the Ingolstadt site. The Neckarsulm site is being expanded as a competence center for the development of the h-tron technology. With the Audi A7 Sportback h-tron quattro prototype vehicle, Audi has the opportunity to enter the volume-production process once the market and infrastructure justify such a move. The company is therefore committed to expanding the filling station infrastructure.
Even the classic technology areas in the automobile, such as combustion engine, power transmission and suspension offer many more ways of reducing fuel consumption. Audi leverages these opportunities to the full with a host of new technologies.
Efficiency is a result of intelligence, in other words, of knowledge and putting that knowledge to use. The principle of the predictive efficiency assistant (PEA) is based on this maxim. Audi offers this function in some of its larger models. The assistance system knows the data for the navigation route and points out areas to drivers in advance where they should take their foot off the gas, such as on downhill stretches of road or speed limit zones. If required, it automatically controls the freewheeling of the automatic transmission. It can improve fuel economy on highways by up to ten percent in this way.
A classic engine topic in the modular efficiency platform is the cylinder on demand (COD) technology; Audi offers it with the 1.4 TFSI, the 4.0 TFSI, the 5.2 FSI and the 6.3 FSI. In the partial-load range it deactivates half of all cylinders, restoring them as soon as the driver accelerates hard. COD reduces fuel consumption substantially when driving moderately, particularly with the four and eight-cylinder models.
The belt starter generator (BSG) is about to go into volume production. As soon as the driver takes their foot off the gas, the generator can recoup up to 5 kW of energy; in the new 48 V electrical system the savings are a formidable 12 kW. The BSG works closely in conjunction with the combustion engine; as a result, the engine can be run in many situations closer to its ideal load point and thus more efficiently. Fuel savings of up to 0.7 liters per 100 kilometers can be achieved overall.
Another 48 V project is still at the prototype stage – the eROT system is located in the chassis. The electromechanical rotary damper (eROT) replaces today’s hydraulic damper. A strong lever arm absorbs the forces acting on the wheel carrier with a sporty driving style and on rough roads. It transmits this force to an electric motor, which converts it into electricity, through a series of gears. At the same time, the eROT system acts as an actively controllable damper.
One of Audi’s goals is to increase the efficiency of its vehicles without compromising on traction and driving dynamics. Engineers are therefore looking for savings potential in all technology areas. They found what they were looking for with the quattro permanent all-wheel drive.
Longitudinally mounted engine at the front, transversely mounted engine at the front, mid-engine at the rear – the Audi models adopt very different drive concepts and provide the right quattro drive for each model. For the very latest mid-sized model lines with longitudinally mounted engine, quattro is now available with ultra technology. If the automobile is being driven at moderate speed and the all-wheel drive does not offer any advantage, the new system simply drives the front axle. If the quattro drive is then actually required, it is activated in two stages – as part of a predictive, responsive process.
Control of the new quattro drivetrain operates predictively. Networked throughout the vehicle, it acquires and evaluates data – in ten millisecond cycles – such as the steering angle, transverse and longitudinal acceleration and engine torque. From this data the control unit computes, for instance, the point at which the front tire on the inside of the curve will reach its grip limit during fast cornering; it computes this around one-half second in advance. If the wheel approaches the grip limit at a defined threshold value, the all-wheel drive system is activated.
The control unit’s decision on whether to predictively engage the all-wheel drive is primarily based on the driver’s style of driving, the status of the Electronic Stabilization Control (ESC) and the mode selected in the Audi drive select system. In the reactive engagement, the system reacts to sudden changes in road friction. These changes might occur, for example, when the wheels go from dry asphalt to a sheet of ice.
The quattro with ultra technology offers major benefits in terms of efficiency without seeming any different from permanent systems in terms of traction and driving dynamics. The key difference to competitor solutions relates to the concept of the two clutches in the drivetrain. In this way, Audi eliminates a large part of the additional fuel consumption which the quattro drive produces by its very nature. Despite the new, additional parts, the quattro with ultra technology is nearly four kilograms lighter than the previous system.
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Within the framework of our holistic approach, we take into consideration not only fuel consumption and CO₂ emissions, but also the entire value chain of our products and processes.
This includes analyzing and evaluating all phases of the life cycle – starting with the production process and progressing to the use phase and on to recycling. We have set the goal of reducing every new model’s environmental impact compared to that of its predecessor.
The Audi life cycle assessment (LCA) serves to quantitatively assess such ecological aspects as greenhouse gas emissions (including CO2), energy consumption and the potential for acidification or summer smog. When compiling the LCA, Audi follows a procedure that conforms to the international ISO 14040 ff. series of standards.
In addition to evaluating ecological aspects, the assessment considers all phases of the vehicle life cycle – production of the materials and components, manufacturing of the vehicle itself, and recycling. The decisive factor, however, is the utilization phase, when around 80 percent of the emissions occur for conventional drive concepts running on fossil fuels. In its life cycle assessment, Audi estimates a vehicle will clock up 200,000 kilometers. The level of emissions is directly affected by the choice of drive concept and the vehicle’s consumption, but also, for example, by the fuel production process. With renewable fuels such as Audi e-fuels, and with renewable electricity suitable for powering electric vehicles, the utilization phase counts for less, making the vehicle manufacturing process more significant.