Significantly reduced emissions
The developers at Audi chose the world’s cleanest diesel technology as the unit best befitting the Audi Sportback concept car. The six-cylinder 3.0 TDI clean diesel is equipped with a system for the effective reduction of nitrogen oxides.
The diesel engine development engineers at Audi have combined an entire package of innovative measures for this latest TDI generation: The piezo common rail system with an injection pressure of 2,000 bar, highly efficient exhaust gas recirculation and optimized turbocharging result in significantly reduced raw 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 installed on any engine in the world, marking yet another Audi innovation.
Comprehensive emission control system
The status of the new-generation TDI as the definitive clean-running, high-tech diesel is sealed by the downstream exhaust emission control system, which reduces emissions by up to 90 percent. The system uses AdBlue, a biologically degradable, waterborne additive that is injected in small amounts upstream of the DeNOx catalytic converter. In addition to the catalytic converter, the exhaust emission control system comprises the metering module, the AdBlue tank and heated lines, as well as an extensive system of sensors. The additional oxidizing catalytic converter and the highly efficient, regulated diesel particulate filter round off the comprehensive emission control system.
Thanks to their extremely low emission levels, these modern direct-injection diesel engines can be put into service anywhere in the world, even in the U.S. state of California, which has the world’s most stringent emissions limits. Compared with the fleet average of the gasoline engines typically found in the U.S., the TDI boasts a fuel-efficiency advantage of up to 40 percent. The diesel technology thus makes a greater contribution than any other type of engine to reducing the consumption of fossil fuels. Audi will offer this engine in the U.S. and Europe beginning in 2009.
As in the U.S. version of the Audi Q7 3.0 TDI, the V6 also produces 225PS and 550 Nm of torque in the Audi Sportback concept. Power is transferred to the wheels via Audi’s most modern transmission: the new 7-speed S tronic. The quattro® permanent all-wheel-drive system ensures that the torque generated by the powerful TDI is also converted effectively into propulsion and dynamism under any conditions.
Weighing just 1,800 kilograms and with a drag coefficient of 0.30, the coupé will accelerate from 0 to 62mph in less than 7 seconds and reach a top speed of 152mph.
Extensive efficiency-optimising measures
The Audi Sportback concept’s average fuel economy according to the European ECE standard is 47.8 mpg, and its CO2 emissions no more than 156 g/km. These sensationally low figures for a car of this size have been achieved by extensive efficiency-optimizing measures covering not only the engine but also its ancillaries.
For example, this model’s electromechanical power steering only consumes energy when the steering is turned, not when driving in a straight line.
The TDI engine features an innovative temperature management system. When the engine is warming up, part of the coolant flow is diverted – another way to improve efficiency, since it helps the engine to warm up quicker. This means significant practical savings, because many journeys are fairly short. The fuel pump also runs only when there is a demand for fuel, and therefore uses less energy.
The 7-speed S tronic transmission is a very efficient unit with a wide spread of gear ratios. For the first time, it has been equipped with transmission oil heating, so that it reaches its intended operating temperature much earlier and therefore has a lower level of internal friction.
When coasting, the Audi Sportback concept – like the Audi A4 and Audi Q5 production models – recuperates energy. This boosts the output of the alternator and is used to charge the battery. This energy, which in effect costs nothing to recover, is fed back into the vehicle’s electrical system when needed. An automatic start-stop system shuts the TDI engine down to save energy, for instance when waiting at a traffic signal.
And when it is on the move, tires optimized for low roll resistance cut fuel consumption significantly without incurring any disadvantages in the performance area.