EN
This paper is a continuation of the previous articles of the authors, published in Polish Maritime Research[1, 2], devoted to pollution of the atmosphere due ship diesel engines in operation. In the paper presentedare results of the investigations carried out in the Gdynia Maritime Academy laboratory with the use ofa ship one-cylinder diesel engine combusting heavy fuel oil. Two its possible malfunctions : changes of fuelinjection pressure and changes of injection advance angle were simulated. Both malfunctions, which mightoccur as a result of incorrect engine regulation or wearing or contamination of engine elements, weresimulated separately. The presented investigations were focused on finding out relationships between theassumed malfunctions and exhaust gas content, especially content of nitric oxides (NOx),very toxic compo-unds.The paper is ended by several conclusions arising from analysis of the results which have - apart fromtheir cognitive merits - also an utilitarian character as they may be put into practice by ship operators,provided that some limitations resulting from the specific conditions of the reported laboratory investiga-tions are appropriately taken into account