Audi announced that it will begin production of a new generation of TDI diesel engines in mid-2008. The new diesels will use an optimized combustion process and an ultra-low emission system to comply with US EPA Tier 2 Bin 5 requirements as well as future European standards.
In making the announcement about its new diesels, Audi also touched on its other efforts to improve vehicle efficiency and reduce CO2 emissions, including the development of a power management system with regenerative braking; a new start-stop system; selective hybridization for certain markets; and its backing for alternative fuels such as Biomass-to-Liquids (BTL) diesel and compressed natural gas.
The first of the new 2008 diesel engines will be three-liter V-6 units for the Audi A4 and Audi Q7. These engines will develop 176 kW (240 hp) and deliver peak torque of 500 Nm (369 lb-ft) in the Audi A4 and 550 Nm (406 Nm) in the Audi Q7.
Additional models will follow in rapid succession, with Audi seeking to extend the new technology to other vehicle classes and power categories by 2010.
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.—Rupert Stadler, Chairman of the AUDI AG Board of Management
The new diesels will feature a new piezoelectric common-rail system with an injection pressure of 2,000 bar. Combustion chamber sensors will enable more precise regulation of the combustion processes. A combination of efficient exhaust gas recirculation and optimized turbocharging will deliver a sharp reduction in engine-out emissions.
A downstream urea SCR aftertreatment system will reduce emissions of oxides of nitrogen (NOx) by up to 90%. The emission system comprises the catalytic converter, the metering module, an AdBlue tank and heated lines, as well as an extensive system of sensors. The emission control system is rounded off by a separate two-way catalytic converter and an electronically controlled diesel particulate filter.
Audi will market these new models in the USA and in Europe from the second half of 2008.
Power management and hybridization. Looking beyond the engine and aftertreatment systems, Audi is developing a power management system for both diesel and gasoline models that captures and stores energy during coasting and braking for use in vehicle electrical systems. Audi is also developing a start-stop system for its vehicles. These approaches are similar to the actions BMW is taking across its 1, 3 and 5 Series models. (Earlier post.)
Audi is developing hybrid systems for a number of its models and says that it 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 in 2005. (Earlier post.)
Fuels. In addition to its backing for BTL diesel in the form of the SunFuel facilities backed by the Volkswagen Group, Audi noted that it is developing a CNG engine based on the TFSI gasoline engine.
The CNG concept is retains its performance even when running in natural-gas mode, and offers a reduction in CO2 emissions of up to 20%. The placement of the natural gas storage tank still allows full use to be made of the luggage compartment.