Outlook of a brand in terms of drive
Directional drives
Everyone involved knows that Audi has committed itself to the global advertising slogan “Vorsprung durch Technik”. The customer expects it and those responsible in Ingolstadt are aware of their duty. After the most recent events around the diesel and ultimately around the gasoline engine, the automobile manufacturer from Upper Bavaria is setting the course for the next few years. It's not about making both drives disappear. On the contrary, both the gasoline engine and the diesel, which is much scorned around the world, will be modified and integrated. For this, Audi got help from an external agency. Dr. Nikolai Ardey, long-time engineer at the competitor from Munich, started the project “Efficiency and Driving Fun” in Ingolstadt on January 01.01.2017st, 2.500. A total of 2025 employees work in Audi's development centers around the world. Parts of the project are the further development of the traditional V-engine strategy, Audi's g-tron models with Audi e-gas, mild hybrid technology and the implementation of new test cycles and emission regulations. In addition, the trend towards e-mobility should not be neglected. The declared goal at Audi: by 1, the Ingolstadt-based company would like to offer a mix of 3/2 electric motors and 3/XNUMX conventional motors. Ambitious goals that are not only popular with customers in Germany. The Upper Bavarians showed us their first results at the end of May this year in individual workshops and in small driving presentations around the airport of the Bavarian capital.
V-engines: technology in cooperation
Audi has been developing V engines for 30 years now. It all started in 1988 with the 3,6 liter eight-cylinder V8. Two years later, a 2,8-liter V6 followed in the Audi 100. After a few more steps, the Ingolstadt engineers used V6 and V8 engines in all models based on the modular longitudinal construction kit, i.e. in the Audi A4 and A5 series , A6, A8 as well as Q5 and Q7. The V6 units - diesel and gasoline engines - use their power from 3,0 liters of displacement, while the V8 engines have 4,0 liters. The power range extends from 160 kW (218 hp) to 445 kW (605 hp). In order to minimize development costs, Audi entered into a meaningful cooperation with the luxury brand from its own group at the beginning of the last decade. Porsche supports the Ingolstadt-based company with the V8 engine in the joint project house. In return, Audi offers the car manufacturer from Zuffenhausen the expertise and know-how of the V6 engine. The current status of both drives is the V8 in the Porsche Panamera and the V6 in the new generation of the Audi A8, which will be coming to the Frankfurt International Motor Show on time this year. With the next step in view, both units are suitable for hybridization on a 12-volt and 48-volt basis.
Intermediate step with electric motor - mild hybrid
Arrived at the destination, not only the engineers of the car manufacturer drive purely electrically. Until then there will be one or the other stage of development. One of them is the not so new, but effective hybrid technology. From the middle of this year, Audi intends to continue what a Japanese carmaker had already offered its customers before the turn of the millennium into the next generation of its luxury saloon A8. In the so-called mild hybrid (MHEV, Mild Hybrid Electric Vehicle), an 48-Volt network will be operating on board in the future. In Japan, long considered overpriced, the concept for Audi is apparently no problem, because the hybrid is suitable, according to Dr. med. Nikolai Ardey for both gasoline and diesel engines. Initial tests have shown a reduction in fuel consumption of the V6 petrol engine, taking into account the New European Driving Cycle (NEDC) of up to 0,7 liters per 100 kilometer. In contrast to other conventional technologies, the MHEV drives even increase comfort by allowing silent sailing at higher speed ranges up to 160 km / h.
The general mode of operation of a mild hybrid is designed to be as simple as it is simple. Electric and combustion engines sit on a crankshaft. The electrical unit supports the "everyday" work of a motor. Starting, boosting and recuperation. But Audi wouldn't be Audi if the engineers there didn't come up with another refinement. The Audi system consists of the two components of a water-cooled belt starter generator (RSG) and a lithium-ion battery with 10 hours of charge carrier capacity and a 48-volt voltage level. The generator at the front of the engine is connected to the crankshaft with a V-ribbed belt. This means that the RSG has up to 12 kW of recuperation power and 60 Newton meters of torque. The 12-volt network used so far is coupled to the main on-board network with 48-volt voltage via a DC / DC converter. The lithium-ion battery in the luggage compartment is roughly the size of a large lead-acid battery and is permanently cooled by air cooling. The “sailing” associated with the mild hybrid was previously only possible at low speeds. With the increased voltage of the on-board network, the driver now allows between 30 and 160 km / h to take off the accelerator so that the vehicle can "roll" for up to 45 seconds with the engine completely switched off. When sailing at a low speed, the start-stop phase begins at 22 km / h.
That the MEHV technology remains just one step, Audi already proved for this year's Geneva Motor Show. The Q8 Sport concept was presented under the motto "Electric rolling, powerful boosting". The start generator used there should deliver 20 kW and 170 Newtonmeter. The increased energy efficiency of the recuperation of the system brings the 3.0 TFSI engine in combination with a power transfer of up to 700 Newtonmeter torque. The show car accelerates with 350 kW (476 PS) system performance in 4,7 seconds from 0 to 100 km / h and further up to 275 km / h top speed. The MHEV system is intended to reduce consumption of the concept study by about one liter per 100 kilometer. That promises at least a lot of driving pleasure and sovereignty.
Energy turn major
In search of alternative drives, Audi took a turn in 2013 with natural gas (CNG - compressed natural gas) and the company's internal Audi e-gas (a synthetically produced fuel). The Ingolstadt engineers hope to achieve almost CO2-neutral mobility. The A3 Sportback g-tron (combined consumption of up to 3,6 CNG) will be followed by the A2017 Avant and A4 Sportback in early summer 5. Both models should not exceed the CNG consumption of 4,5. A further developed 5 TFSI unit will work in the A2.0 Sportback, which is equipped with pistons and valves specially adapted for optimum compression. The engine's output is 125 kW (170 hp) and 270 Newton meters. In future, the A4 Avant will work with the same engine in CNG mode. Its 2.0 TFSI engine accelerates the vehicle, which is exclusively combined with an S-tronic transmission, from 0 to 100 km / h in 8,4 seconds at a top speed of a whopping 221 km / h. We were able to convince ourselves of the acceleration and top speed values around Munich Airport at the end of May this year. We noticed positively that the original grumpy engine noises in CNG operation have given way to those of a conventional gasoline unit. Despite the driving pleasure in both Audi models, efficiency has not fallen by the wayside. Compared to gasoline, burning natural gas produces around 25% less CO2.
When operating with the sustainable Audi e-gas, which is chemically identical to natural gas, the car manufacturer from Upper Bavaria takes another step towards sustainability. The fuel is produced with the aid of green electricity from water and carbon dioxide or also from residues, such as straw and green waste. To make this alternative "tasty" for customers, Audi offers this fuel to its customers as standard for three years. The customer refuels his g-tron vehicle at any CNG filling station and pays the regular price. Audi is thus securing the corresponding reduction in CO2 by returning the calculated quantity in the form of Audi e-gas to the general natural gas network. This is done automatically on the basis of surveys and service data of the g-tron cars. TÜV Süd will monitor and certify the procedure. The g-tron customers also receive certification for this.
Audi has its own power-to-gas plant in Werlte (Emsland, Lower Saxony). The plant, which was also put into operation in 2013, generates up to 1.000 tons of e-gas per year, which binds a total of 2.800 tons of CO2. With this amount, around 1.500 Audi g-tron vehicles per 15.000 kilometers per year should be almost CO2-neutral. Audi expects the smooth conversion of electricity into fuel. It should be possible to store surpluses of renewable energies in the long term. After Werlte, new cooperation partners are bound. The Thüga Group and Viessmann GmbH are the next partners. At the beginning of May this year, the parent company, filling station operators and gas network providers announced a joint declaration of intent to continue to stick to CNG mobility. The aim is to bring one million CNG vehicles to the road across all brands by 2025. 2.000 filling stations nationwide are to support the project up to that point. The expansion at European level is not neglected.
Global testing and emission process
The European Driving Cycle (NEDC), which has now been in existence for more than 20 years to determine consumption and emission values, has seen a change of guard not least from the events of the recent past. It will be replaced by the WLTP (Worldwide Harmonized Light Duty Test Procedure) from September 2017. The global procedure is intended to map more realistic data and to do justice to the changed traffic and driving conditions in Europe. Additional emission measurements are required to take account of the new standards, such as the new exhaust standard 6c. To support this, measurement in ongoing road traffic (RDE - Real Driving Emissions) is mandatory.
Audi will use the WLTP that leads to a uniform test procedure for cars and light commercial vehicles from September 01, 2017. The binding date of application for all automobile manufacturers is January 01, 2019. Until then, the NEDC value will continue to be the basis of taxation for the customer. The much more dynamic WLTP value shows more acceleration and braking than the NEDC. It contains four phases: up to 60, 80, 100 and 130 km / h. In this way, different driving situations - from inner-city traffic to motorway driving - are mapped. The WLTP, like the NEDC, is still determined on the dynamometer. The new top speed is 10 km / h higher than the NEDC to 131 km / h. The new test cycle also outperforms the old one in terms of both duration (30 minutes) and average speed (46,6 km / h). The route length on the roller dynamometer corresponds to around 23 kilometers instead of 11 kilometers previously.
And finally ... With new ideas and innovations, the car manufacturer from Ingolstadt reinvents itself again and again and again in the service of its customers. That this happens in consideration of the environment is once more worthy of all honor.
Text: Stefan Beckmann, cover picture: manufacturer, image: Stefan Beckmann and manufacturer
