Bosch systems for engine exhaust treatment are making commercial vehicles even cleaner and more economical. The "Denoxtronic" metering system from Bosch, in conjunction with an SCR catalytic converter (Selective Catalytic Reduction), helps to reduce nitrogen oxide emissions by up to 85 percent. At the same time, the engine can be configured to consume up to five percent less fuel as compared with other approaches to reducing harmful emissions. Particulate emissions can, moreover, be reduced by up to 40 percent by optimizing processes within the engine. The system permits commercial vehicles to achieve, even today, the limits specified in the Euro 5 emissions standard that will apply as from 2008.
The cleaning process is triggered by the AdBlue reducing agent, which is injected into the exhaust gas flow in precisely measured quantities. This gives rise to ammonia, which reacts with the nitrogen oxides in the SCR catalytic converter to yield harmless nitrogen and water. The job of Denoxtronic is to accurately meter the AdBlue, which is stored in a separate tank. The metering control unit, which is networked with the engine electronics, adjusts the quantity of AdBlue injected in accordance with critical engine parameters such as operating temperature and engine speed. The optimum quantity is therefore always injected. The Bosch Denoxtronic reducing agent metering system is modular, and can therefore be used in a wide range of vehicles and different models.
The combination of the Denoxtronic and the SCR converter also means a cash benefit for carriers, particularly in Germany. Companies who convert their fleet to operate at the lower harmful emission limits even before Euro 5 is introduced can save two euro-cents per kilometer on the commercial vehicle toll that they have had to pay on German motorways since 2005. And that is no mean sum: every truck that covers 100,000 kilometers on the motorway can save up to 2,000 euros each year. The second generation of Bosch Denoxtronic is already in series production: in the first Denoxtronic generation, compressed air supports the injection of AdBlue. Denoxtronic 2 manages without the help of compressed air. It consists of fewer components, and can be fitted into a vehicle more easily.
With the "Departronic", Bosch also offers a diesel fuel-metering system for commercial vehicles for the regeneration of particulate filters. In this system, Departronic injects an accurately measured quantity of diesel into the exhaust flow. The fuel oxidizes in the catalytic converter, releasing heat. The downstream particulate filter uses this additional heat to burn off accumulated particles. The robust Departronic, which needs absolutely no servicing, controls the addition of fuel flexibly, and independently of the engine's injection system.
