Effective exhaust gas purification through quick, precise injections of urea solutions

The purification of exhaust gas provides an effective contribution to environmental protection and to the improvement of life quality in cities with large ports, thereby reducing nitrogen oxide and fine dust particles. For such purposes, urea solutions, among other things, that can be injected into the diesel exhaust are used. These systems are called Selective Catalythic Reaction (SCR): With a reducing agent (e.g. Urea/AdBlue® or DEF), NOX is further treated in an exhaust gas catalytic converter which is connected downstream of the engine. DEF is first broken down with ammonia and water. Following that, the ammonia reacts with the nitrogen oxide in the exhaust gas, and NOX is decomposed into nitrogen and water.

The injection of DEF must be permanently quickly and precisely adapted to the concrete amount of exhaust gas produced – in particular, during load changes or changes in performance requirements. Reliability is also required: if the SCR systems malfunction, the ships are no longer permitted to arrive in the port.