25 years of TDI: The Bestseller for Efficiency

The electric biturbo is powered by a separate 48V circuit, which in itself opens up further future possibilities for CO2 reduction, with engine ancillaries and HVAC units potentially diverting less power from the ICE. Another opportunity being explored with 48V is the development of electric chassis control systems. A certainty is using the 48V circuit to produce a 48V mild hybrid that will take the advances mentioned already for future stop-start systems even further.

Audi is also investigating the possibility of using steel pistons in its TDI engines. Their greater thermodynamic properties give advantages in combustion that lead to a reduction in fuel consumption and emissions levels. Already Renault has announced that its 1.5L K9 diesels will switch to steel pistons shortly and deliver a 2% fuel economy benefit.

Injection pressures for common rail diesel systems have risen inexorably since their introduction. Higher injection pressures allow greater control of combustion to reduce emissions, more power and fuel economy benefits. In 2004, Audi's Bosch supplied common rail system was at 1,600 bar, today it stands at 2,000 bar and for the near future it is working on introducing 2,700 bar that would take it close to the 3,000 bar of its TDI race engines. Whether the higher system pressure, combined with future emission regulations would mean the end of solenoid injectors for some of its diesel programmes Audi would not divulge, although it's safe to say that solenoid injectors have been written off before and found a way back.

Similarly, turbo boost pressures are another area of development for Audi. It points out that boost was at 2.3 bar in 2004 and had increased to 3.2 bar in 2014, but with their race engines at 4.0 bar there is a clear opportunity to increase turbo boost further.

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kjclow said:

Sounds great on the technology front but I have to wonder how much of this we will ever see in North America.

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Ironman11142 said:

wish that VW would stand behind their products more and have more competent technicians at their dealerships...

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TDIMeister said:

ANALYSIS: TDI technology at the core of Audi's powertrain strategy

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