Frankfurt: Audi shows its new A4, with a green concept before the even greener vehicle arrives

Just as Audi's cousins at Volkswagen have their BlueMotion range of models (as well as the ECO2 from Renault or the ECOnetic from Ford, just to name a couple), Audi is introducing a low-emission concept in Frankfurt, called e Concept. The picture shows the presentation of the 2008 A4.

The model is based on the current 2.0 TDI engine (which I think is the best-seller at the VAG group in Europe). The car has an impressive consumption for a compact sedan of about 4.9 liters/100km (48 MPG) and CO2 emissions under 129 g per km, which is less than the average the EU plans to become mandatory in 2012. The engine is good for 143 HP at a peak torque of 320 Nm (236 ft lb).

Audi manages those respectable figures by installing piezo-electric injectors in the engine and modified piston geometry to improve thermodynamics and reducing internal friction. To make it the cleanest diesel available, Audi added an ultra low emissions system which will be standard on the 2008 3.0 TDI engine. This engine meets mandatory regulations expected from 2014.

The car has a lower friction manual gearbox with longer rations from third to sixth gears as well as a new Start/Stop system that shuts the engine off when the car comes to a standstill and the driver presses the clutch. Once the driver releases the clutch to start, the engine comes back to life in less than two tenths of a second.

In addition to that, the car stores kinetic energy into gel batteries, making it a micro-hybrid although this energy is used only to power the alternator, so the car saves some energy from the engine at coasting or higher demand (like BMW). Since it's not only the engine that creates pollutants in the car, the A/C system uses a heat exchanger which saves 20 percent of fuel.

Finally, the A4 has some aerodynamic tweaks such as lowering the body about 20mm and installing better wheels.

Full press release after the jump.

[Source: Audi]

More drivability, fewer emissions

  • Just 4.9 litres per 100 km – the new Audi A4 2.0 TDI e Concept
  • The world's cleanest diesel in the new Audi A4 and in the Audi Q7
  • More powerful yet more efficient – the latest generation hybrid module

More dynamism with less and less fuel consumption – Audi is pursuing a consistent strategy to achieve further reductions in emissions. With three concepts that are virtually ready for series production, Audi is using the IAA to present the technology of the near future. The new A4 2.0 TDI e Concept consumes just 4.9 litres of fuel for 100 kilometres, and thus represents a milestone in the sporty middle class. The world's cleanest diesel engine will enter series production in 2008 in the new A4 3.0 TDI with ultra low emission system. The latest generation of hybrid module makes use of the superior parallel hybrid construction and of state-of-the-art technologies such as lithium ion batteries.

Just 129 grams of CO2 – the 2.0 TDI e Concept

With the new 2.0 TDI e Concept, Audi is showing just how effective its new Modular Efficiency program is. The sporty middle class saloon undercuts the consumption limit of five litres per 100 km. The A4 2.0 TDI e Concept needs just 4.9 litres for 100 km on the EU cycle. This means CO2 emissions of just 129 g/km – less than the limit that the European Union aims to introduce for vehicle fleets from 2012. With an output of 105 kW / 143 bhp and a peak torque of 320 Nm, the A4 2.0 TDI e Concept is a powerful saloon – for Audi, a dynamic character always goes hand in hand with low consumption.

In this vehicle, Audi has realised a whole package of innovative engineering solutions. Some of these are already in series production on the new Audi A4. Others, such as the start/stop system or the energy recuperation system, will be introduced in the near future.

TDI marries efficiency with dynamism

The 2.0 TDI in the new Audi A4 presents itself in an essentially enhanced form. A common rail injection system supersedes the unit injection pumps used to date, its piezo injectors supplying fuel with a pressure of up to 1,800 bar, allowing extremely fine atomisation in the combustion chambers. This improves fuel combustion and smooth running.

The refined engine develops a powerful 105 kW / 143 bhp of output. Even in the speed range between 1,750 and 2,500 rpm it puts a bullish 320 Nm of torque onto the crankshaft – this mighty pulling power at low revs is a one of the great strengths of the TDI principle. Modified piston geometry improves the thermodynamics in the combustion chambers. Other measures to reduce internal friction and for temperature management further increase fuel efficiency.

On the A4 e Concept, the 2.0 TDI engine is supplemented by the ultra low emission system. That means that this engine not only works highly efficiently, but it is also exceptionally clear and absolutely future-proof: Even today, it undercuts the strictest European emissions levels, which are not expected to come into force until 2014. The ultra low emission system, which makes the TDI the world's cleanest diesel, will go into series production in 2008 as an option on the new Audi A4 3.0 TDI.

Low-friction gearbox

The TDI's power is transmitted onto a newly developed six-speed manual gearbox that is characterised by greatly reduced internal friction. It has been specially tailored for the high-torque of the TDI engine – its transmission ratios are slightly longer in third to sixth gears. Like all Audi gearboxes, its gear changes are playfully light and extremely precise. The gear change indicator in the driver information system encourages an economical driving style. It indicates which gear is selected and if another gear is judged to be better while driving steadily, it will show this as a recommendation.

An especially fast and smooth start

Another important contribution is made by the start/stop system. It avoids the engine running inefficiently when the vehicle is stationary. This is important because much of our day-to-day driving is made up of trips that are shorter than ten kilometres, and these are interrupted by numerous stops at traffic lights.

As soon as the A4 2.0 TDI e Concept comes to a standstill, the gear lever is moved to neutral and the driver takes his foot off the clutch, the TDI is automatically switched off. The engine is restarted when the driver depresses the clutch. The TDI runs up while he is engaging the gear. It has reached idling speed by the time he releases the pedal. A specially developed starter motor turns the engine in little more than two tenths of a second – 60 percent faster than a conventional part, and yet especially comfortable acoustically.

Microhybrid gathers energy when coasting and braking

The recuperation system on board the A4 2.0 TDI e Concept converts kinetic energy into useful electrical energy as the vehicle decelerates. An innovative gel battery is used as the power source for the vehicle electrical system. This is extremely robust even at high loads and when it is heavily discharged, allowing it to achieve a particularly long service life.

When the A4 2.0 TDI e Concept is coasting or braking, the secondary voltage from the D/C converter is run up. The alternator is now able to convert the kinetic energy into electrical energy that is temporarily stored in the gel battery. When the saloon subsequently accelerates again, the battery feeds the energy back, relieving the load on the alternator.

The power steering has also been thoroughly modified – its effectiveness has been improved by around 50 percent because it is now fed hydraulic energy by a demand-controlled vane-cell pump. In contrast to conventional power steering pumps, which constantly recirculate large volumes, it only pumps as much oil as actually needed at that very moment.

On the automatic air conditioning system, Audi uses an innovative, thermostatically controlled refrigerant circuit with an internal heat exchanger. Along with intensive precision work on other components, has greatly improved the efficiency of the system – the new automatic air conditioning system requires 20 percent less fuel that its predecessor model did.

Sporty performance yet highly efficient

The A4 2.0 TDI e Concept glides smoothly and effortlessly through the wind. Its body is fundamentally extremely aerodynamic. Its boot lid has been given a slight additional separation edge. Specially designed alloy wheels improve the airflow across the wheels and wheel arches, while a sporty tuning has lowered the body by 20 millimetres. This modification reduces the frontal area, improving air resistance.

For Audi, efficiency means exactly the same as dynamics. For example, the tyres are configured for light running, but still have a sporty performance – they have the wide, visually attractive 225/50 R17 format. Yet the most impressive evidence of the potential of the A4 2.0 TDI e Concept is found in its performance figures. The middle class saloon sprints from 0 to 100 km/h in just 9.3 seconds. Its top speed is 215 km/h. A spurt from 80 to 120 km/h in 5th gear needs just 8.7 seconds.

Just 119 g/km CO2: the Audi A3 1.9 TDI

Audi models with the letter e unite efficient energy use with high dynamics. The Audi A3 1.9 TDI e and A3 1.9 TDI e Sportback achieve a standard fuel consumption of just 4.5 litres per 100 km and CO2 emissions of just 119 grams per km. And yet the two models with an output of 77 kW (105 bhp) have a top speed of 194 km/h.

In the near future, Audi will vastly expand the range of such especially efficient models, offering e-models as TDI, FSI and TFSI in the high-volume model series. The Audi A4 2.0 TDI e Concept shows what such a concept could be in the new A4 model series. By the year 2012, Audi will have reduced the CO2 emissions all from its models by around 20 percent and in doing so have bolstered their sporty, sophisticated character even further.

The cleanest diesel in the world

With the new Audi A4 3.0 TDI with ultra low emission system, Audi is demonstrating the future-proof potential of the high-tech TDI engine. From mid-2008, the cleanest diesel in the world will be available in the sportiest saloon in the middle class. It fascinates not only with the dynamics of its 176 kW / 240 bhp and outstanding peak torque of 500 Nm, but also with its low fuel consumption figures and extremely low emissions.

Right from the very start, the A4 3.0 TDI with ultra low emission system will satisfy the emissions limits due to come into force in Europe from 2014, and the LEV II BIN 5 standard valid in the USA. The cleaning effect of the system is also seen in the levels of NOx nitric oxides, which have been reduced by 90 percent. And yet it works more effectively than any other technology on the market.

Audi is not starting its systematic TDI strategy in the second half of 2008 on the A4 alone. The Audi Q7 will then also be available with the world's cleanest diesel engine. Here peak torque will be an amazing 550 Nm. Additional models will quickly follow. By 2010, Audi plans to offer the new technologies in other vehicles segments and power classes.

Innovative technology for minimum emissions

The engineers in diesel engine development at Audi have combined a whole package of innovate measures for this latest TDI generation. The new piezo common rail system with an injection pressure of 2,000 bar, highly efficient exhaust gas recirculation and the optimised turbocharger produce greatly reduced raw emissions. Combustion chamber sensors, a world first, are one highlight. These enable the combustion processes inside the engine to be regulated even more precisely – yet another Audi innovation.

The latest TDI engine ultimately becomes the clean high-tech diesel when it is combined with the ultra low emission system. This reduces nitric oxides by up to 90 percent. This system uses the additive AdBlue, a biologically degradable water-based solution. A minute dose is injected into the system upstream of the DeNOx converter. The ultra low emission system comprises the catalytic converter and a metering module, the AdBlue tank and heated lines, and an extensive system of sensors. The additional oxidation catalytic converter and the highly efficient regulated diesel particulate filter complete the comprehensive exhaust emissions control system.

Great potential for global reduction in fuel consumption

Thanks to these minimal emissions, modern direct injection diesel engines can be used anywhere in the world, even in California, where the world's strictest emissions regime applies. Compared to the fleet average for the spark-ignition engines, the most common power system in the USA, the TDI has a consumption advantage of up to 35 percent. This means that diesel technology more than any other current power system can help to reduce the consumption of fossil fuels.

The latest TDI with ultra low emission system confirms Audi's pioneering role in implementing low-consumption technologies. When Audi put the first TDI into series production in 1989, it was a remarkable milestone in technical progress. TDI rapidly developed into a synonym for supreme pulling power and maximum efficiency, and it thus became a trendsetter for the entire automotive industry. Until today, no other drive system has managed to beat the turbocharged direct injection diesel for agility and low fuel consumption figures under real-life operating conditions.

Extensive package for reducing CO2 emissions

For Audi, perfecting the TDI is part of the integrated technology strategy for further reducing CO2 and other emissions in all its models. All in all, Audi is relying on the great potential of its modern combustion engines. With direct injection and turbocharging, plus high torque with reduced cylinder capacity and lower losses due to friction, the TFSI spark-ignition engines, like the TDI diesel engines, have the best consumption figures available today.

The latest generation hybrid module

For specific requirements in certain markets, it makes sense to complement the combustion engine with a hybrid module. At the IAA, Audi is presenting a drive train model with the latest generation of its hybrid drive concept. Because of its straightforward, modular structure, it can be fitted to any Audi model with a longitudinally installed engine, and it can be combined with almost any combustion engine. Audi will put its hybrid concept into series production as soon as this provides decisive benefits for the customer. Of course Audi sets very high standards for the quality of the hybrid drive – it must rival the efficiency of the latest Audi TDI technology.

The Audi hybrid module is configured as a single-shaft parallel hybrid. Here, the electric motor/generator is integrated into the drive train between the engine and gearbox. As a so-called full hybrid, this system can run on either the spark-ignition engine or the electric motor, or combine the power of the two. When it is coasting or braking, kinetic energy is converted to electrical energy, fed back into the battery and converted to forward propulsion as necessary.

Parallel hybrid is most efficient solution

The principle chosen by Audi is that of parallel hybrid – a new solution in this class that has a potential superior to the competition. It is more efficient than any other system currently on the market, especially when driving long distances and on motorways. In addition, its spontaneous response makes sporty-dynamic driving possible. This allows us to retain Audi's typical handling characteristics, even with a hybrid drive.

An important basic factor for the high efficiency of the hybrid drive is an extremely efficient combustion engine. The Audi 2.0 TFSI is characterised not only by its very high 155 kW / 210 bhp of output and its peak torque of more than 300 Nm, but also by its very low fuel consumption. Its opposite number on the electrical side also represents an optimum of efficiency and power density. The electric motor, a permanently excited synchronous motor, develops a further 32 kW / 44 bhp of output and it peak torque of 230 Nm practically from standstill.

Eight-speed tiptronic with electric motor

The electric motor is integrated in the housing of the eight-speed tiptronic gearbox, which is also new. The complete unit does not need any additional installation space. Space has been created by doing away with the hydraulic torque converter. A dual-mass flywheel absorbs vibrations from the Audi hybrid module, while a wet multi-plate clutch takes care of coupling and decoupling the combustion engine and the electric motor.

A large portion of the high-tech competence of the Audi hybrid module can be found in the precise control of this clutch. The combustion engine is started and stopped extremely quickly and quietly, so that is can hardly be noticed by the passengers. The hybrid drive is configured for purely electric driving at speeds up to about 50 km/h and a range of about three kilometres. That is ample for a large proportion of inner-city driving.

Especially compact battery guarantees usability

The energy for this comes from a lithium-ion battery of the latest design. Compared to the nickel metal hydride technology currently in use, the size and weight of this system is reduced by about a half with a comparable performance.

Its operating voltage of 264 volts comes from a battery pack that is just 26 litres in size. Its maximum output is 39 kilowatts. The Audi hybrid module allows the volume of the luggage compartment and its usability to be maintained without restriction.

Innovative brake system for optimised energy regeneration

The electric motor regenerates a major part of the battery charge when the vehicle is braked – so-called recuperation. A completely new brake system enables hydraulic and electrical braking power to be variably mixed. With this system, electrical braking power is optimally tuned to the charge state of the battery, up to a maximum of 30 kW, and the rate of energy regeneration is increased significantly compared to previous systems. The feeling at the pedal and the braking distance are not affected by this.

Just 100 kilograms additional weight

For this, the latest generation of hybrid module, the engineers have optimised every component with regard to function, size and weight. The power steering is powered by an electrohydraulic pump. Similarly, the air conditioning compressor and the vacuum pump for the brake booster are electrically driven.

The ABS and ESP driving stabilisation systems have been extended in their functions and have fully integrated the electric drive components in their control regime. The additional weight caused by the hybrid is now a mere 100 kilograms.

Just 6.4 litres standard fuel consumption

The combination of 2.0 TFSI engine and hybrid module presented at the IAA achieves all the driving performance of a high-displacement, naturally-aspirated six-cylinder engine. In particular its extremely spontaneous and powerful pulling away characteristics guarantee the dynamism that is typical of Audi. This pioneering combination has a fuel consumption that is about 30 percent lower that a conventional spark-ignition engine. With a vehicle weight of 1,850 kilograms – corresponding to a luxury class saloon or a medium size SUV – its fuel consumption in the standard cycle is just 6.4 litres per 100 kilometres.

A clear course into the future

With its integrated efficiency strategy, Audi is systematically working on achieving further reductions in fleet fuel consumption. The combustion engine will remain the major drive system for the foreseeable future. Already an extremely efficient principle, the TDI still has considerable potential for further reductions in fuel consumption, and the ultra low emission system is the guarantee that it remains absolutely future-proof. The TFSI principle and the Modular Efficiency programme will guarantee significantly reduced CO2 emissions for all new model series. Finally, TFSI engines, complemented by hybrid modules, could represent an alternative to the TDI in certain markets.

And one thing is indisputable for Audi. Efficiency and reduced fuel consumption will never be achieved at the expense of the brand's other strengths. Audi will retain and bolster its sporty-elegant character, drivability and the high quality standards of its models, even as emissions are further reduced.

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