25 April 2008

Volkswagen announced at the Vienna Motor Symposium this week that it would introduce a production version of the BlueTDI next-generation turbo diesel for the North American market in the US Jetta this summer.

The common rail engine is based on the high-tech TDI, which was introduced in Europe in 2007 with the Tiguan. This engine already satisfies the Euro-5 standard that comes into effect in autumn 2009. For US operating conditions, the four-cylinder engine was redeveloped with internal engine modifications and a NOx trap.

Jens Hadler, director of Volkswagen Powertrain Development, said: “High fuel prices and a dramatic change in environmental consciousness means that diesel is becoming more and more attractive for American drivers every day.”

Hadler said the engine could reach up to 60 miles per US gallon which is an improvement of 12 per cent over its predecessor.

A key aspect in the development of the BlueTDI (2.0 litre engine displacement, 103 kW/140 PS, 320 Nm) is the reduction of nitrogen oxide emissions (NOx); the American Bin5/LEV2 standards stipulate a nitrogen oxide limit of only 0.05 g/mile. VW met this limit and a general reduction of raw emissions by using internal engine modifications and the maintenance-free NOx trap.

The changes include modifications to the design of the injection system of both the American and European TDI as well as the use of cylinder pressure sensors. This allows for a completely new type of cylinder pressure-based combustion control, which is both faster and tailored to each specific cylinder. Also new on-board is an optimised high-pressure injection pump.

Another feature is the combination of a high-pressure exhaust gas recirculation system with low-pressure exhaust gas recirculation. This dual system is an effective means of reducing nitrogen oxides in the engine. The dual circuit EGR system alone reduces NOx by up to 60 per cent.

Outside the engine, the NOx trap – connected downstream of the oxidation catalytic converter and the particle filter – reduces nitrogen oxide further. Implemented together, these measures reduce nitrogen oxide emissions by 90 per cent.