For the most powerful engines, the step up to Euro 4 has some attractive benefits. Operating economy matches the best Euro 3 performance of Scania V8 engines. And you also get increased power, increased torque, and even better driveability. 

The SCR technology developed for Scania engines has been evaluated by Scania customers. These extensive field trials covering millions of kilometres have established suitability of Scania SCR for both Euro 4 and Euro 5, the latter enabling customers to take immediate advantage of road fee incentives in Germany that will apply until October 2009. 

Why SCR?
Scania SCR is highly successful for trucks transporting heavy loads over long distances with high cruising speeds. In these circumstances, maintaining the right exhaust temperature for the engine is important for optimising performance and economy with low emissions. To ensure adequate cooling reserves on the most powerful V8 engines, Scania SCR will be used to achieve Euro 4. It is also used for the V8 and inline 6 engines complying with Euro 5.

SCR is an after-treatment that requires a urea-based additive to reduce NOx emissions. The urea is injected in the exhaust to maintain a reaction in the catalytic converter, which is integrated in the silencer. 

Economy comparison.
A Scania Euro 4 V8 engine with SCR is efficient at highway speed with high engine load and high gross weight. Compared to a theoretical comparable engine with EGR there will be a small advantage in fuel consumption. However, this advantage will be countered by the additional cost and of the essential urea additive.  The effort needed to acquire and store the urea solution on board and at the home base has to be considered, as well as the space and weight on the chassis. 

As with Scania EGR-equipped engines, the overall operating cost of Scania Euro 4 engines with SCR, including urea, will be similar to comparable Scania Euro 3 vehicles.