NOx out of diesel engines - the necessity of thermodynamic considerations

This article describes the exhaust gas reduction in diesel engines under special consideration of thermodynamical aspects. In order to avoid the emission of NOx, procedures are described which minimize the production of NO and NO2, preserving the advantages of the diesel engines. The aim is to minimize the fuel consumption and to maximize the power simultaneously. In which way is it possible to convey this knowledge successfully when teaching chemistry in schools? First a table of nitrogenoxides with their different oxidation states is presented enabling the pupils to discover the possible redox reactions and the electron transfer. Subsequently experiments at the microscale level are discussed. These experiments can be carried out as student experiments, but it is also possible to project them in the classroom.