The Volkswagen Group will achieve CO2 emission levels of 95 g/km by 2020, with some brands below that figure and others slightly above it, Prof Dr Ulrich Hackenburg, board member for technical development Audi, said.
One of the main planks for achieving this target will be the growing sophistication of diesel engine technology with SCR, lean NOx traps “and combinations of that” beyond Euro6, he said speaking at an event celebrating a quarter of a century of TDI diesel engine technology.
Under a programme that was described as “rightsizing” rather than “downsizing” Hackenburg didn’t dismiss the possibility of future larger vehicles having a combination of smaller diesel engines with electric powertrains.
“There will be an acceptance with the right amount of torque and performance,” he said, adding: “The challenge of diesel is not performance, it’s more how we can manage NOx in combination with performance. We will use all the technologies we can – 48-volt electrification, starter-generator and electric compressors – to give the customer what they want whilst reducing emissions.”
Part of that arsenal on display included a bi-turbo three-litre V6 delivering 385PS and 750NM between 1250 and 200rpm with 62mph reached in only four seconds in an RS5.
What makes this engine unique is an electric compressor that spools up to 70,000rpm in 250 milliseconds delivering a maximum of 3.2bar boost to the smaller of two exhaust gas driven turbos, eliminating any lag, until that turbo is on boost right through to 3000rpm when the larger, second, turbo comes into play.
The electrical booster is powered by a separate 48-volt system and a lithium-ion battery which is charged by recuperative braking, so the car’s 12 volt system is not drained of any energy. The 48-volt system can also be used to power auxiliary functions such as the air-conditioning and power-steering systems to further improve overall engine efficiency.
This engine is expected to appear in the new, sporting, version of the second generation Q7 in 2016.