Audi Cleaner TDi Engines

From mid-2008 Audi will be putting the cleanest diesel technology in the world into series production. The new TDI engines with their ultra-low emission system combine the spontaneous performance and superior pulling power of today’s TDI power units with outstanding fuel consumption figures and incomparably low emissions. Indeed, they will already undercut the most stringent emissions limits that are to be applied in the future in Europe as soon as production starts. Just as the entire Audi range complied with the Euro 4 standard and the forthcoming Euro 5 emissions limits years in advance, the Ingolstadt brand is once again set to assume its role as the pioneer of groundbreaking technology.

For Audi, the trendsetting TDI engine is a core element of its integrated technology strategy. “We intend to consolidate the status of the TDI as a highly efficient form of propulsion on a sustained basis. And in future we will be launching ‘e’ model variants designed for optimised fuel consumption in the high-volume model series – either in TDI guise or as petrol models with state-of-the-art TFSI technology,” says Rupert Stadler, Chairman of the AUDI AG Board of Management.

Maximum efficiency is the recipe for success

“Audi is a trailblazer when it comes to diesel power. Since 1989, over 4.5 millions cars have rolled off the production line with the highly efficient TDI technology under the bonnet. By equipping the R10 TDI sports prototype with this technology, we have just won the 24 Hours of Le Mans with a diesel-powered car for the second time. The Audi R8 racing cars with TFSI petrol direct injection took victory on five occasions at Le Mans. We have been incorporating the key findings from the world of motorsport directly into series-production development,” emphasises Michael Dick, Board Member for Technical Development at AUDI AG. “By so doing, we are demonstrating how TDI and TFSI represent the ultimate in efficiency, driving pleasure and economy both on the road and on the racetrack.”

The latest TDI generation sees Audi reaffirm its leadership claim in the field of ultra-sophisticated diesel technology. When Audi started up series production of the first passenger-car TDI engine in 1989, it marked a key milestone in the advancement of automotive technology. Audi TDI soon became a byword for supreme pulling power plus maximum efficiency and, what's more, the pacemaker for the automotive industry as a whole. Even today, the spontaneous performance combined with extremely low fuel consumption achieved by the turbocharged direct-injection diesel engine remains unsurpassed by any other drive system under realistic conditions.

Consistent strategy throughout all model series

With its latest generation of TDI engines, Audi is now out to prove that this high-tech drive unit still has high potential and a guaranteed future: thanks to the optimised combustion process and the inclusion of an ultra-low emission system, these models comply with the BIN 5 emissions requirements in the US as well as meeting the toughest standards expected to come into force in Europe for the foreseeable future.

Audi is kicking off its consistent TDI strategy for 2008 with the three-litre V6 units in the Audi A4 and Audi Q7. Developing 176 kW (240 bhp) and a supreme peak torque of 500 Nm in the Audi A4 and 550 Nm in the Audi Q7, they boast the sublime dynamism combined with relatively low fuel consumption that is the hallmark of any Audi. Additional models will follow in rapid succession, with Audi seeking to extend the new technology to other vehicle classes and power categories by 2010.

Innovative technology for minimised emissions

This new technology from Audi takes the TDI principle of diesel direct injection with turbocharging that has been proven a million times over and launches it into a whole new dimension. To do this, the diesel-engine development engineers at Audi have incorporated a whole raft of innovative measures into the latest TDI generation: the new piezoelectric common-rail system with an injection pressure of 2,000 bar, the extremely efficient exhaust gas recirculation and optimised turbocharging bring about a dramatic cut in untreated engine emissions. One of the highlights are the combustion chamber sensors that enable even more precise regulation of the combustion processes in the engine – this is the first time that such sensors have been fitted on any engine in the world, marking yet another Audi innovation.

The status of the new-generation TDI as the definitive clean-running, high-tech diesel is sealed by the downstream ultra-low emission system which reduces nitrogen oxide emissions by up to 90 percent. The ultra-low emission system runs on a biodegradable additive in the form of a solution called AdBlue. Tiny doses of this solution are injected upstream from the DeNOx catalytic converter. The ultra-low emission system as a whole comprises the catalytic converter, the metering module, the AdBlue tank and heated lines, as well as an extensive system of sensors. The comprehensive emission control system is rounded off by the separate two-way catalytic converter and the highly efficient, electronically controlled diesel particulate filter.

Great potential for reducing fuel consumption all around the world

Thanks to their extremely low emission levels, these cutting-edge direct-injection diesel engines can be put into service anywhere in the world, even in the US state of California where the most stringent emissions limits are enforced. Compared to the average fleet consumption of petrol engines typically fitted in the USA, the TDI offers a fuel saving of as much as 35 percent. As a consequence, diesel technology can make a greater contribution to reducing the consumption of fossil fuels and emissions of environmentally harmful greenhouse gases than any other form of propulsion currently available. Audi will be marketing these new models in the USA and in Europe from the second half of 2008.

Hybrid systems for a number of models

Nevertheless, there may also be a call for a hybrid system designed for individual markets and to meet specific requirements. Audi is developing hybrid systems for a number of model series and will put them into series production wherever it sees this as producing significant benefits for customers. Audi unveiled the Audi Q7 hybrid study with an electric motor integrated into the driveline between engine and gearbox back in 2005. Designed as a “full” hybrid, as it is known, the Audi Q7 can run on either the petrol engine or the electric motor alone or be powered by both in unison. During phases when the vehicle is coasting or braking, kinetic energy is converted into electrical energy, fed to the battery and then transformed into propulsive power as and when required.