The target of this thesis was to optimize after treatment system of a diesel engine to meet the new emission standards. The aim was to transform AGCO Power Ltd 44AWF -diesel engine to pass the emission standard of Stage 5. The work was done because of the tightening exhaust standards, which require the introduction of new technologies also from the manufacturers.

The study was started by performing a combustion calibration on the engine, after which the amount of nitrogen dioxide produced by the oxidation catalyst was studied. It was contemplated whether an oxidation catalyst provided with a lower catalyst amount would be sufficient to permit passive regeneration of the particulate filter. Subsequently, the optimum level of urea spraying was sought with the selected oxidation catalyst.

An experimental study was executed at the engine laboratory of Turku University of Applied Sciences during summer 2017. The study was carried out in cooperation with AGCO Power Ltd which provided motors used in the study.