Volkswagen has completed the development of the next generation turbo diesel

At the recent International Vienna Motor Symposium, Volkswagen an-nounced the production of the BlueTDI, a next-generation turbo diesel developed especially for the North American market. This is in keeping with the fact that five US states including California, currently have the strictest emissions standards in the world (BIN5/LEV2).

With the key aspect of the development of the (2-litre, 140 bhp) Blue TDI being the reduction of nitrogen oxide emissions (NOx) (the American BIN5/LEV2 standards stipulate a nitrogen oxide limit of only 0.05gallons/mile), the BlueTDI is actually a common-rail diesel that was first introduced in Europe in 2007 with the Tiguan. This engine already satisfies the Euro-5 standard that comes into effect in autumn 2009. In order to meet specific operating conditions in the US, this four-cylinder engine was redeveloped with internal engine modifications and a NOx trap. The VW engineers in Wolfsburg, Germany, met this limit and the general reduction of raw emissions by using internal engine modifications, some of which are unique worldwide, and implementing 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 implementation 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 unique feature is the combination of a high-pressure exhaust gas recirculation system with additional low-pressure exhaust gas recirculation. This dual exhaust gas recirculation (dual circuit EGR) 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 of the engine, the NOx trap is connected downstream of the oxidation catalytic converter and the particle filter, which reduces nitrogen oxide to an absolute minimum. Implemented together, these measures reduce nitrogen oxide emissions by 90 per cent.

According to Dr. Ing. Jens Hadler, director of Volkswagen Powertrain Development, the high fuel prices and a dramatic change in environmental consciousness means that diesel is becoming more and more attractive for American drivers every day. "This motor will help the diesel get its big break in America because it consumes so little and yet can go such long distances on a single fill-up. And in a country as big as the United States, this is a priceless advantage. On the highway, for example, this engine can reach up to 60 miles per gallon. This is an improvement of 12 per cent over its predecessor, which had a lower capacity and higher emissions", added Hadler.

Interestingly, the Blue TDI, in spite of variations in fuel quality, which are more dramatic in the US than in Europe, meets these emissions standards. The engine is slated for commercial introduction in the US Jetta soon. The Jetta has been the most popular and successful European-manufactured car on the American market, especially as a diesel.