Dosage of AdBlue in SCR systems is especially difficult, due to the possibility of precipitation of ammonia deposits within the exhaust system. Excessive ammonia emission from downstream of the reactor, so called ammonia slip, is also problematic. Intensive research and development work is currently being carried out in order to limit the occurrence of these unwanted phenomena. One of the methods used is optimisation of the algorithm controlling AdBlue injection or modification of the dosage system. Other innovative solutions like, for example, heating and evaporating AdBlue before it enters the exhaust stream before SCR reactor are also being researched.